One of the first things new owners find is that the cup holders in the Thor A class rigs are terrible. Cup holder mods have been covered in these forums multiple times already but I am putting this thread up there for people searching for answers in the future. This method has been covered in the past so I am standing on previous posters' shoulders here.
I went the PVC coupler method. It was cheap, easy and I am happy with both the appearance and the functionality of the end product.
Schedule 30 3"x3" PVC coupler sourced from Lowes, $1.58 each x 4. Not all local Lowes had this part listed as in stock, which other threads here had warned of. I had to go across town to a different Lowes than I normally go to in order to pick this up. Other threads mentioned they are easy to source at plumbing supply houses.
Krylon COLORmaxx Flat Black Spray Paint and Primer In One, also sourced from Lowes, $3.98.
Scotch Mount Double-Sided Mounting Tape Clear 1" x 60", sourced from Target, $4.99
I sanded the PVC pieces before painting them. I think in retrospect I might have picked the gloss black instead of the flat black but I am still happy with the results. After the paint dried I wrapped what would end up as the bottom of the PVC piece in the mounting tape and peeled off the outside part of the tape. Now it is just a matter of shoving them down into the cupholder until they reach the bottom. The tape is thick enough that it creates a solid connection between the PVC pipe and the bottom of the cupholder. If need be I am confident I could wrestle the pipe back out if I really wanted to, but it sure isn't just going to fall out.
The wife is quite happy with the aesthetics and the usability of the results, and I was able to do four cupholders for about $16 or so.