40 or 45 ft 5fer, any difference

Good point Burbman. There is a mindset that goes with pulling a longer rig, once you past the 35' threhold, which is sort of the safe length that ensures you can fit into most places there is no turning back.
If you choose to stop at 40' or go for 45' you need a sort of adventorous I can squeeze this rig in anywhere attitude.
Now some can do without all the squeeze it in drama and choose a 35' rig to avoid the challenges a longer rig creates.
However if you can get it done with a 40 rig you can likely get a 45' in as well.
Over the course of a camping season I imagine there are 2-3 times when I manage to squeeze my 40 rig in that I don't think anything larger would have made it.
However the TV plays a factor as well. Length of TV and turning radius become a major factor when it comes down to squeezing an oversized rig into a site.
For the record I now have a 40' rig, if I found a floorplan I loved that was longer I would not hesitate to go to a longer rig.

Hold on, lemme get my calculator...the difference between 40 and 45 ft. is....lessee....5 feet!

Seriously, 40' is already locking you out of many state/national parks and older CGs, if you're gonna go 40' you may as well go 45'.

The bigger you go all you are getting is more floor space & more storage space. The furniture is the same size. The stove is the same size. The fridge is the same size. The only thing bigger is likely to be the TV.

As pointed out the biggest loss with size is CG options. Once you get past the mid thirties in length your availability in nice SPs, CPs etc. is drastically reduced leaving little choice but the private CGs all jammed together.

Choices & compromises.

A lot of us rushed home in and around March 2020, Joe.

Our rig is 42' towed with a Silverado dually CC LB. I'm getting to the age where a smaller rig would be more attractive but in the years I've hauled it we haven't had problems staying at private parks and fueling at truck stops. I would never attempt a state or provincial park but if the private parks you stay at has pull-through spots you san be sure that access is good for those sites (but not necessarily all sites in the park).

We had decided that we were going to leave our 5er in Florida and just use a 16' cargo trailer for our motorcycles and other stuff. But March 2020 made us rush home and I didn't want to stay in motels and eat in restaurants so we got a new set of (6) tires and came home in the 5er. I hope to go back this winter and find a place we can leave our 5er 12 months of the year. The cargo trailer is still down there waiting for us.

Not much difference being just a few feet, either way you will be restricted primarily to private parks and newer federal and state parks that have sites for longer rigs. We have always had long RVing combos whether with towable RVs or with our current 40' class A and toad, we have always managed to find places to stay and refuel.

Just pick the rig that suits your situation best, there are no perfect RVs as every floorplan can be improved and or modified depending on your viewpoint. As for RV manufacturers, they all put out crappy products no matter the price point or branding, I always make improvements to any of the rigs we have had in the past 30+ years of RVing anyway.

No real difference backing. If you want the LONG RV get it.

You will not see that much difference between the two. We went from a 40 foot dp Class A to the rig in my sig. I do not have any problem fueling or with site restrictions due to length. Our class A had a Toyota Highlander as the dinghy too. Granted you will not be able to stop at a lot of Mom and Pop fueling stations but that has never been a problem for us either.

At that size, you are looking at private campgrounds with large sites regardless. I doubt you will notice much difference getting in and out of sites.

As mentioned, once on the road, there isn't much difference between a 20ft and a 45ft 5er (a little but not a lot)

Moving down the highway, length is not a problem. The challenge is fueling (have to stick to truck stops or a very open stations), entrance roads to rv parks and maneuvering within the rv park. My rig is 42’ and pulling with a SRW CC short box Ram 3500. So I have a decent radius. My problem is I have nearly 16” of rear overhang. Tail swing on my rig is horrendous, as is many of the larger rigs in this size range. Even though I realize it is present, it has still bitten me in the @ss three times now.

So, look for the shortest rear over hang as possible no matter how long you are. If I could do it over again, I would look in the 10-12 overhang area. Even a 53’ box van big rig only has about 10’ of overhang with about a 72’ overall length. King pin to rear axle length is also a consideration. The longer that measurement is, the more room you need to turn that combo.

Larger rigs are challenging to say the least, and some rv parks are a bit unforgiving. I drive a 63’ transfer truck for a living and don’t have as much trouble with it as I do my 57’ of rv and truck.

Good luck on your quest. And safe travels.