Welcome to the boards.
Start with a soild roof, then a soild foundation, replacement windows, as much insulation as you can fit in the attic (R50) proper ventalation in the attic, up dated wiring, if these are good then all the other stuff is just fluff and can be done later.
It always amazes me how many people have leaking old roofs, old windows, $300.00 plus per month heating bills and there trying to redo a kitchen or bathroom.
When all that's straight only do one room at a time or you will go nuts.
I've had people ask me to fix plaster ceilings, when I tell them I will not fix the ceilings until the roof is fixed. There was missing shingles, and missing panes of glass on the second floor. There reply was we can not afford to fix the roof.