Canopy for my Fith wheel questions

I think 41' is too short. You will not have enough protection for the front cap. Also, when planning, try to imagine whether or not you may change RV's in the future. How big, tall and wide you build your cover will determine the size of what you are able to protect from now on. That is, of course, unless you add on to it. When we built our RV garage, we had no intention of trading so soon but the bug hit and we did. Luckily, we took trading in the future into consideration and built the garage 20x45' with a 15' roll up door. Mind you, that is slab measurement. We should have made sure that was inside demisions as the inside is roughly 18'8"x43'8". We had to be careful when deciding on new fiver because most of the ones that had everything we wanted were rather long. We ended up with a 39'10" fiver. It fits perfectly backed up to wall with room to walk around front. If garage was a little longer, it would be ideal but we are just happy it fits.