I'll add my two cents here too. Also watch for the 'little things' -- they may become insurmountable hurdles. At one point my wife could no longer walk into our accessible bathroom due to a 1/8" difference between the bedroom and bathroom floors. Also be sure you have turning radius room for the toilets, sinks, kitchen work areas, etc. I've seen too many layouts that expect you to back up in your wheelchair and not be able to turn around. Check the tile used in bathrooms for excessive slipperiness. Additionally make sure there is room for ramps to have safe inclines (listed on the ramps we used) and that they can stick out if you have a step into the house from the driveway or garage and not interfere with the car, etc. I'd also echo @rosemarya in wheelchair use! Try spaces out with YOUR chair! They can vary greatly and transfers between chairs for different areas, uses, etc. can get physically taxing very quickly.