Here is my 2 cents take it or leave it.
You have already said if you get rid of the 250 the payment and insurance alone will almost pay for the house. Sell the truck. Get rid of the B2 and the trailer and ATV. You can then afford to buy in cash an Explorer or Ranger and have a good down payment for the house.
You have to figure out if "stuff" (aka crap) is more important than YOUR family. I've been through the having crap is more important phase. It almost destroyed my marriage and family. We live on one income, mine. So far everything we have is paid for in full, I have gotten rid of things that I thought were special to me. Believe me there is nothing more special to me than my wife and boys.
You have to understand that you will have your fiance's income for a while but in this day you have to be prepared to live on 1 income in case something happens. Say your lovely future bride gets pregnant next year and goes on mat leave? Can you afford all the 'crap', house, and additional expenses of a little one? What if one of you gets in an accident and is off for 6 months or more? Can you live?
Forget all the commercials and garbage out these days about all the crap you HAVE to have to be happy. It is all a load of BS. To be happy you need your family, a house, and be able to afford the basics of life. If that means selling all the stuff you have now to buy an older car, or fix the B2 properly for transportation then so be it.
I'll step down from the pulpit now or else I could go on for some time.