We use ours at least once every trip... In fact, when we camp at my aunt and uncle's property, we need the stock 25 cord, a 50' extension, our 100' 12 gauge extension cord, and an additional 150' to reach the receptacle around the back-side of their cabin. We were only running the converter, a small box fan, and the fridge on our popup, so there was no issue with too much voltage drop due to the length.
After we upgraded to the TT, we used the extension cord every trip but one... A couple of them would have required VERY awkward placement of the trailer on the site to reach.
In the rare case where I need more power cord can I use a 50 amp to 30 amp adapter and just use my 30 amp extension added to the 50 amp? I know I won't have the 50 amps but I could make do on 30 amps if necessary.
You do understand that will limit you to a SINGLE 30A circuit for 3,600 watts, where with a 50A connection you have TWO 50A circuits for 12,000 watts?
As long as you are OK with that your suggestion will work for the very few times you will need to do it.
1999 Sunnybrook 27RKFS Fiver.
2005 GMC Sierra 2500HD CC/SB/DA 2WD, LLY with LBZ air cleaner, 52 gal Titan tank, Bilsteins, Line-X, Westin steps, Prodigy, Retrax cover, 16K Superglide, 5th-Airborne pin-box, Multi-vex mirrors, TST TPMS.
We end up using our extension about twice a year at different campgrounds. Alot of what you will need is based on where you tend to camp. I've only needed a 50 to 30 adapter once and it was provided at a campground in Indiana with no charge. They only had 50 amp connections. Never have used or needed one since.
Do what other state using the 30 amp extension and you will be great.