I currently own a trailer house that has a 100 amp service. I am going to be getting a manufactured house that has a 200 amp service. My question is I have a 200 amp service ran into a box under my meter which has 2 circuits in it right now. One circuit is 100 amp for the trailer and one is a 30 amp for a well. Is it going to be all right to change the 100 amp circuit to 200 and still leave the 30 amp circuit in the box?
Shawn... service changes can be very dangerous, so I hope you aren't considering doing this yourself. I'm rewiring my house, including a new main panel, but the service upgrade (which will be done after the branch circuits are done) will be done by an electrician.
As for 'design choice', I would have the well pump run off a circuit breaker in the main panel. Down the line, you may decide to have a generator, either whole house or selected circuits. At that point you'll be in a much more flexible position for placing your well circuit if it's on one of the breakers in your new panel.