Or you can simply just use the RV lanes. I've seen trucks and fifth wheels in them and I've pulled the TT we had (35' in total length) with a super crew cab f250 without any issue.
I've forgot to mention it in the many threads on here, but besides the bigger discount and ease of the RV Plus Card, I like that it doesn't stop at $75 or $80 like most other places do when I use my visa debit card. I wish there was a Flying J or Pilot near me that was convienent to use as I would just fuel up there all the time.