What does M-72 Light Anti-tank weapons have to do with anything? You have more to worry about in regards to Russian or Chinese manufactured weapons that are both newer and more potent. What makes the M-72 so nice, is it's lightweight so you can lug one around without effecting your remaining loadout to much, which like it was used in the Battle of the Black Sea (ergo Blackhawk down) can be used for other things then anti-tank duty. Base detonating shaped charges (ie HEAT) have existed since the Second World War. Not to mention the light towed guns anti-tanks guns that were effective during at the first part of WW2, but then armor increases have made it so ATRs or AT grenades only really work well in urban terrain where you have enough hiding spots, and ability to funnel to manage to use them on critical spots.
The scenario you posted indicates the major problem was the roadways were to narrow for even trucks. That kind of limits the size of a big, clunky mecha to roughly landmate or smaller size. Of course, now you've increased your weight significantly (clue: polymers and ceramics weren't really a happening engineering material back then so we're talking pure steel) making compensating for your already high ground pressure that much harder, which is going to make any part of the terrain that isn't solid, even more problematic. Additionally your ability to traverse rough terrain is mainly due to that fact _you_ are small, full sized vehicles aren't. Of course, there are things like motorcycles, which are nice and small. Otherwise it is purely a function of how much the leg can be raised. Plus due to your weight and height just standing on a slope is going to involve you having to compensate for the moment created simply by gravity. This kind of hurts the one type of terrain legs have a true advantage in efficiency, ie upward slope.
Why would Germans with Panzerfausts or HMGs have had the slightest difficulty nailing your mountain mecha and reducing it to scrap? Especially as you're now a big obvious thing (clue: engines make noise, small engines requiring lots of power like those on motorcycles make even more noise), not to mention it is nowhere near as able to use cover and concealment, and these nice narrow roads happen to funnel you so they know right where to put their guns. Which likely would include towed artillery and possible recoilless rifles, although I'm not sure they had those back then. Let's just not get into the fact the expenses for the entire project let, alone simple per unit manufacturing cost is going to be considerably higher then German expenses to manufacture a Panzerfaust or HMG belt, and that money and resources aren't going to build other units.
The real question is what the mecha does better, justifying it's mere existence? We're talking something that's very, very vulnerable, with considerable limitations, with a thoroughly out of proportion price tag and logistic footprint for the firepower it could potentially bring to the field. Machining operations under ideal conditions take a while to get through something like real armor, so any melee weapon you rig up is at best going to perform at those levels and likely worse. Sheet metal, and stuff like that isn't a big problem, but then all you need is an abrasive water jet to rappidly rough cut things like that.
Plus if like suggested the density is cut, you cut the mass and in so doing both the inertia that resists recoil and the pilot from being put into cardiac arrest from sympathetic vibrations even if it could somehow stop autocannon and up.
EDIT: Actually the problem as you described it is the trucks can't get through, which means you can't move your troops or logistics worth anything. Unless this mecha is also a unbelievable pack mule extrodinaire, it doesn't matter if it's made of Magiranium armor that defies CoM, CoE, etc and runs on everlasting Maginol, because they can't move the troops through there easily enough to use it as an invasion corridor if they can't get the trucks through.
The scenario you posted indicates the major problem was the roadways were to narrow for even trucks. That kind of limits the size of a big, clunky mecha to roughly landmate or smaller size. Of course, now you've increased your weight significantly (clue: polymers and ceramics weren't really a happening engineering material back then so we're talking pure steel) making compensating for your already high ground pressure that much harder, which is going to make any part of the terrain that isn't solid, even more problematic. Additionally your ability to traverse rough terrain is mainly due to that fact _you_ are small, full sized vehicles aren't. Of course, there are things like motorcycles, which are nice and small. Otherwise it is purely a function of how much the leg can be raised. Plus due to your weight and height just standing on a slope is going to involve you having to compensate for the moment created simply by gravity. This kind of hurts the one type of terrain legs have a true advantage in efficiency, ie upward slope.
Why would Germans with Panzerfausts or HMGs have had the slightest difficulty nailing your mountain mecha and reducing it to scrap? Especially as you're now a big obvious thing (clue: engines make noise, small engines requiring lots of power like those on motorcycles make even more noise), not to mention it is nowhere near as able to use cover and concealment, and these nice narrow roads happen to funnel you so they know right where to put their guns. Which likely would include towed artillery and possible recoilless rifles, although I'm not sure they had those back then. Let's just not get into the fact the expenses for the entire project let, alone simple per unit manufacturing cost is going to be considerably higher then German expenses to manufacture a Panzerfaust or HMG belt, and that money and resources aren't going to build other units.
The real question is what the mecha does better, justifying it's mere existence? We're talking something that's very, very vulnerable, with considerable limitations, with a thoroughly out of proportion price tag and logistic footprint for the firepower it could potentially bring to the field. Machining operations under ideal conditions take a while to get through something like real armor, so any melee weapon you rig up is at best going to perform at those levels and likely worse. Sheet metal, and stuff like that isn't a big problem, but then all you need is an abrasive water jet to rappidly rough cut things like that.
Plus if like suggested the density is cut, you cut the mass and in so doing both the inertia that resists recoil and the pilot from being put into cardiac arrest from sympathetic vibrations even if it could somehow stop autocannon and up.
EDIT: Actually the problem as you described it is the trucks can't get through, which means you can't move your troops or logistics worth anything. Unless this mecha is also a unbelievable pack mule extrodinaire, it doesn't matter if it's made of Magiranium armor that defies CoM, CoE, etc and runs on everlasting Maginol, because they can't move the troops through there easily enough to use it as an invasion corridor if they can't get the trucks through.