I did what you are considering.
My panel had spare slots and I just bought a 15 amp plug in circuit
breaker at Lowes or Home Depot. I put the outlet in the toe kick area
right next to the panel and it only required about 5 feet of 14/2 romex.
Get a plastic "old work" outlet box and a duplex outlet and cover plate.
It's a 1 beer job if you have ever done anything like this before.
The 2nd dedicated outlet allows us to perk coffee and run a floor space
heater at the same time. Or toast bread and run a heater.
We've never tried to run 2 heaters at the same time.
I suspect Lou is correct in that might trip your 30 amp either in your
trailer or on the pole depending on what else is on.
IF your electric water heat element came on while you were toasting
and heating or microwaving it would probably trip.
We've never tripped ours knock wood
Also you can run an outdoor extension cord from the duplex outlet
on your power pole and snake it inside thru a slide seal or other hole
and power a heater like that with no modification at all.