I run everything in my 30AMP trailer when plugged into 15/20AMP Receptacle at home. No problems at all. The only thing I have to watch out for is not have two high wattage things on at the same time otherwise it will trip my house breaker...
My extension cord connected to the house is 10 gauge HD (10-3) Contractor type cords. I also use the RV30A-15A LONG DOGBONE type adapter (WALMART)... I have used a 12-gauge setup a few time but would not recommend anything smaller than 12-guage extension cord. Also do not use any of those small round RV30A-15A adapters. They will get hot on you eventually and burn up your shore power 30A Plug...
I have two trailers connected to different 15A/20A circuit breaker zones at the house and is on 24/7 when my trailers are parked at home.
Been doing this for years... I feel the connections whenever I am near them and they always stay cool to touch.
We stay in our trailers off and on alot when parked at home. A great get-away/// Always doing mods to my OFF-RoAD Trailer when at home so having it hooked up aids me big time there.
Roy Ken