Welcome to iRV2
Sorry you're here with problems .
Smoke from the front and CEL on , I can think of about 5 different very serious problems that could be happening .
Have you checked all the engine fluid levels ?
If you look up at the engine from under the coach do you see any drips ?
Did the smell from the front remind you of oil or rubber burning?
Did you notice the dash volt , temp or any gauge on the dash give a reading out of the normal range before the CEL came on ?
Sorry , I can't come to grips with the question about " hydraulic levelers open "
If you have hydraulic levelers you want them " retracted " or " stored " before you move the coach.