So are you at the time of your life your family has grown and left the nest or are you beyond that and thinking of retirement? Whichever your goals are probably similar. Faced with a houseful of stuff, yours and yours kids. Where to go now and what size house?
First thing to think about is the stuff! Determine a timeframe to declutter. Once you have less you will feel free. Rent a storage unit. Toss, sell or donate and the rest put in storage. Have your kids come get their stuff, offer to pay for storage for one year. After that it is theirs to get rid of or pay for.
Once you are down to what you will keep it will be easier to determine what size house you will desire or need. Usually less space which ='s less money. Less money for house purchase, utilities bills, taxes,etc.
Time to move on!