I guess it depends on what you hope to do, and if you like to walk. Stay near where the things are you want to do.
I Chaperoned a High School Baseball team to a tournament and we stayed at Circus Circus which is near the north end of the strip. We were there 8 days and I walked the strip from Circus Circus to Mandalay Bay several times when I had a few free hours. Took me an hour each way. About 6 miles each way. So to me, the strip is an easy walk if you don't have mobility issues. But I am a walker, and a fast one at that. I walk 2 miles (to Target and back) on my 30 minute lunch break every day, which amazes some of my co-workers who are literally half my age.
I do recall the room taxes being pretty steep, especially since we got such a cheap rate at Circus Circus.