What to do first?

Congrats on the new house. If it were me, and if the roof and foundation were in great shape, next I'd bring the electricity and plumbing up to code, all these protect your interest and keep you and yours safe. Then I'd invest in improvements to heating, and next invest in windows, installation, and such that will keep energy expenses down. Last I would take care of the cosmetic things like floors and inside walls.

And the best advise is thoughout all this restoration...it might be necessary to chant...."this too shall pass...this too shall pass..."

Hugs
marlene

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It is the one with persistence and determination that brings great ideas into being.

In frame double pane replacements can be had for around $100. They don't take much work to put in, you basically pull the inside trim off that holds the windows in, take out the existing windows and tracks, slide in new double pane windows and tracks, and put the trim back up.

First thing to do is prioritize: What must be done now, what can wait and be done later, what would you like to do.

Must: Plan for the furnace issue to be handled before heating season.

Must: Fix the leaky windows.

Need: Verify the electrical system is safe ( outlets and switches ).

Want: Floors and walls. ( I would personally rip the carpet out if its dirty/smelly and leave the floors as is after a good cleaning for now. I detest smelly/dirty carpet. I'd rather walk around on clean wood floors that need refinishing. ) If the walls are in good shape, why rip them out? Maybe spackle and paint?

Evaluate as time passes: Roof. hey, if it isn't leaking, don't bother with it for now, sock some money away for that rainy day when it starts to give problems. If any flashing is loose or missing, fix it. If any shingles are missing or loose, fix them. You can make that roof last quite a while most likely.

If you are like us, money is an issue as well. I have a list of things that need to be done around our place, when funds are tight I go thru the list and pick things I can do with materials and tools on hand already. A lot of stuff can be done with minimal materials, mostly effort and time is involved.