How long is too long to travel In a fifth wheel.

We are at 39' and haven't had any issues over the last 5 months with the length, only with campgrounds being full.

We plan our travel day to be at ~3 hours. I figure how far that will get us and use RV Park Reviews.com to start my search. I review the ratings but look for parks that are marked for big rig access.

May take several calls to find a site, but we always manage to find something near our mark.