Congratulations on both your upcoming Marriage and re-establishing your credit score after a bankruptcy!
I would suggest you continue to work on your credit score until you can raise it to the 620-640 range as this will afford you a better chance at a low down payment loan such as an FHA , with a first time home buyer assistance program. There are several available in the Riverside County area that you could potentially qualify for.
As for Buying with your fiance', Please consult with an Attorney and a good leander as to the potential liabilities, both positive and negative that could come from buying a home together. On one hand, her credit score could help you , and on the other, you wouldn't qualify for the First time homebuyer progam as she is already considered a Homeowner. Please keep in mind that most FHA and Firtst time homebuyer programs will not lend on a Manufactured home unless strict guidelines are met.
Please feel free to contact me if I can assist you in anyway. I specialize in First time Homebuyers with over 23 years experience and have dealt extensively in Manufactured Housing in the Beaumont area.