Looking to rebuild in older built home is a tall order in many respects depending on needs and wants! Many variables exist with your question.
Do you have any type of construction background or do you have a trade license in electric, air-conditioning, plumbing, or a GC license? In my experience if you cannot do much of the work yourself it will be costly to go green with current codes.
Please check with your local government on grant funds, codes, or a program offering low interest loans for older type homes. (Fix-up-program)
If you are on a fixed budget you might want to pre-plumb for thermal solar and photovoltaic (solar electric) for the future, if you want to keep the home long term. This is not something for a limited budget. However it can be pre-plumbed, and incorporated at a later date when funds or another opportunity from the power company or local government can assist with bringing the cost down.