I guess I should have made myself more clearer.
I would leave the 30 amp panel in the trailer just as it is, but disconnect its feed and remove my 30 amp cord.
Then Install an additional 60 amp breaker panel with a 60 amp main breaker, and a new 50 amp power cord.
I would sub feed the existing 30 amp panel from the new panel and then have additional breakers and capacity in the new panel to feed a washer and dryer, etc
My background is electrical so I see no problems and I would do it all in accordance with the NEC, but I am wondering if there is anything I am forgetting
jack L