Looking for input on home construction

Wasnt sure where to put this so figured i give here a try. So i currently live in a double wide with a detached garage on 2 acres of the family farm i have a garden and small farm animals while im not a 100% homesteader i do raise all my own meats other then seafood and try to grow most of my own vegetables and can them with the addition of a dairy goat herd i hope to start reducing the need to go to the store as often. I have been between the thought of staying where i am as even tho its on the family farm its my father place so i do pay a small amount of rent/mortgage as the place is technically supposed to be handed to me for my years on the farm but i have been throwing around the idea of getting a small plot at a different location and starting from scratch but either way with my relationship becoming more serious and looking like in the near future ill not be alone in my home an need the additional rooms i was thinking of having my current place/ and or new place excavated and a basement poured then setting a modular onto the foundation ive seen this done before and have a relative that did this and there place is looking in good shape still. My thought is it would be cheaper then new stick built home and with a full size basement it would be double the sq ft of my current home as i would finish the basement. I have no clue as to what all goes into this process though. I have been looking for modular homes and wasnt sure what the difference was between a new double wide and a modular could both be permanently set on a foundation? has anyone here done this with any info it would be great to hear input so i can start planning for the future.

I've done modular house sets and completions.  I wrote about it in this post.

Let me know if you have any more questions.

In a cold climate I would go for a modular home not a double wide. Usually the insulation and seal of the house is much better cutting your costs down the road. Dont be stingy on the basement either. Icf if you can afford it foam insulated on the outside as a minimum. If you do stay in place think about having the hard sit down financial talk with dad now and put it in writing. What do both parties expect? What is the time frame? What financial shape is the farm in? Tough tough questions but necessary. We do not do that as a culture but I know at least two examples of people who ended up with nothing who were "supposed" to inherit. An aging dad changed his mind and reversed mortgaged the farm in one case and a sudden death without will and a mother who sold it and split it evenly between all siblings in the other...