I pushed my 80 lb 7 year old around for 8 days last August. It wasn't that bad. We had a place for our stuff and pushing that stroller was easier than walking holding his hand, trying to hold his hand while he bounced, skipped, flapped, tried to wander in a different direction, or just stopped walking for no apparent reason. It was tiring and made me sweat a little but so would have walking holding his hand. He's safer and happier in the stroller. Especially with the visor part over him, it's his own little space to sort of just veg for a few minutes.
He did walk a lot but when he got tired or a little flighty we'd tell him to sit and he'd happily climb in. He also wasn't in it constantly. We'd park it, do one area of a park, then stick him back in it while we moved from one major area to another.