First lets talk about 50A shore power. It has two hot wires, a neutral and a ground wire. If you measure between the two hot wires you will get 220V. If you measure from one of the hots to the neutral you will get 110V.
Larger MHs such as yours often use 50A shore power, so lets assume that is what you have, but they only use the 110V between the hots and neutrals, not the 220V between the two hots. This gives them two 50A, 110V supplies that power two strips of breakers or busses. Generally one buss of 110V breakers powers the routine things and maybe one A/C. The second strip powers the big A/C sometimes in the basement.
When you use an adapter to plug into 30A shore power you are only getting one leg of 110V power. It usually powers the first strip discussed above, most of the routine loads and an A/C but only to 30A. It does not power the second buss so the big basement A/C will not run.
So what do you want: full 50A power with all breakers functional. Then install a 50A/220/110V outlet and use your normal shorepower cord. If that isn't convenient, then install a 30A/110V outlet and use an adapter and live with only one A/C working.
If your home breaker box has available breaker space and particularly two opposite legs available side by side, the difference in cost is small- another breaker at the main panel, wire that costs a bit more for 50A and a bigger breaker and socket at the outside power box. But sometimes inside panels are almost full and even moving stuff around won't work, so you might be stuck with installing 30A, but not likely.
David
