im just now scared of putty tape
Don't be. FWIW, I pulled putty tape off my trailer that was 40 yrs. old that was under trim pieces and it was still good. Putty has a benefit beyond the butyl stuff and maybe your repair guy was able to explain that to you.
I guess no one has told you so let me be the first: Do not use any silicone based sealants on the exterior of your TT. It will probably be fine for areas that don't have any sun on them but is known to fail when exposed to UV and weather. It is also a ***** to remove when you want to add more sealant. Use a polymer based sealant like Proflex RV or a urethane based sealant/adhesive like 3M Marine on exterior surfaces.