I’ve run into this a couple times. I always try to follow the HO instructions, but I also listen to the pets, within reason. And I explain to the HOs what my general pattern is with doggos to see if they’re ok with it. One sit was hilarious. The HO was all “she LOVES her 6 am walks and we’re usually out for at least 30 minutes”. 6 am bleh, but needs must so I was ready to do it. That dog had less than 0 interest in getting out of bed for a 6 am walk. She rarely started moving before 9 am and once I had to literally shove her booty off the bed at 11 am because I had lunch plans. She was hilarious, I loved her. 
I think the HO loves HER 6 am walks and the dog is just dragged along for company but would rather be a bed burrito for as long as possible. We would do plenty of walking though, just more with my general pattern vs following the 6 am thing.
My general pattern is that we do a quick morning pee/poo, as needed. Then a bit later we’ll just start wandering. Walk to the park and have a run then sit and look at a nice view. Walk to a cafe and have a cup of tea and a drink and we can both people watch for a while. Walk to another park and do some sniffing and running around. Find a nice place for an outdoor lunch, walk there, and enjoy some more people watching. Continue our walk and swing through another park for more play time, then head home. All together we’ll be out for 5-6 hours and walking a good bit of the time with rest/water stops in between. Then we’ll do a pre-bed pee break and repeat the next day. I find the dogs like this routine as it gets them out of the house for much of the day, they get to go new places and sniff new things, they get loved on but lots of different people, and they get a lot of good walking and play time. It also gives me a chance to go out and do things/explore without feeling bad about the doggo being home alone. Obviously this won’t work for all dogs in all weather or all locations, but I find most seem to like it and I make sure to choose places to sit that are dog friendly (and clear it with the HO first to make sure there are no issues/concerns about it).
I also have done sits with mis-matched energy dogs and finding a routine for them can be a challenge. I find that throwing balls/sticks for younger dogs and letting them run and expend energy while walking at a more sedate pace with the older dog can work well. Then they both get a nice bit of exercise but the young one also gets to run off that extra energy and I don’t have to walk them separately. One sit I did had an oldie and a puppy so at the start of the walk we’d break a branch off a dead tree and I’d throw it ahead for pupper. Oldie and I would stroll along and pupper would tear back and forth with the stick. We’d walk all the way to the park at the end and then dip our toes in the river and watch the ducks swim/play fetch with pupper until oldie woke from her nap. Then we’d repeat the process on the way back and then both dogs would crash for hours when we got home.