One of my slides was making a thunk. It was the underside wiper seal getting caught on top of the roller as the slide went in. Eventually it wore a hole in the seal causing the wheel to momentarily separate from the slide floor when running over the wiper seal then thunk as it cleared the seal.
Considering you don't have much down time to troubleshoot and pending company joining you, might consider posting on the forum for a mobile repair service in the area you are traveling to or enroute.
2016 RAM 3500 DRW 4x4 LB LoneStar Edition, w/Timbrens, Andersen Ultimate 2, Swift Hitch SH04 WiFi Backup/Rear View Camera
2018 Chaparral 360IBL w/Tireminder SMART TPMS, Furrion Wireless Observation System, Progressive EMS-HW50C
2006 RAM 3500 DRW LoneStar Edition
2011 Starcraft 392BHU w/Andersen No-Sway hitch