We are at the point after 3 decades of RVing with various sizes and classes of RVs, add to that it is now mostly just my DW and I, we went big as we are planning to do extended stays. Appears your new truck is stout enough to handle whatever size rig as even the largest 5ers are being built lighter than ever before.
It is by far our roomiest RV ever @ 40', and yes it might be difficult to get into some of the older RV sites, but we have done so much of that type of camping with our kids it is time to relax and enjoy the spaciousness. We kept our previous RV anyway for those type of trips, although it has been sitting idle for awhile.