Hi J.,
If there aren't other kids in your area, arrange play dates for him. These can include homework time at the beginning, if that's the schedule you want him to follow, but you might want to put off reading time until later in the evening.
BTW, what do you mean by "we" complete his homework? By 10 you should be encouraging homework independence in your child. If he has questions, he should do as much as he can on his own and then come to you with a list.
Your son is also at a good age to consider taking up a hobby. When my son was 10, he was passionately into legos and k'nex, and would build for hours on end. I think it was around this age that we first got him the programmable lego set, which he loved (he's now at college studying computer science and game development). My daughter liked to work with wood and was always outside sawing or pounding nails into one creation or another. (I never could figure out what some of them were, but it didn't matter!) Both of my kids loved to cook and do crafts, as well, and I always had plenty of supplies on hand for them to mess around with. The important thing is to introduce your son to options to let him explore his own creative interests.
Personally, I'm also a big supporter of Cub Scouts/Boy Scouts (and Girl Scouts, too). This program offers wonderful opportunities for exploration, personal growth and achievement. Even though dens typically meet only once a week, at age 10 Webelos scouts have a set of 20 activity badges they work on over the course of 2 years. Many of these have substantial requirements that your son can work on independently. This is not to say that you can't be involved, and you and his father should support him -- just from enough distance to let him grow and find his own interests. Also, if you identify with a particular religion, there are religious emblems that can be earned as part of the program. If you decide to go this route, make sure that you find an active den in an active Pack with committed leadership (especially the Cubmaster). And, if you do join and your son takes to scouting, encourage him to go all the way to earn the Eagle rank. This is usually achieved b/n the ages of 16 - 18 and is a major accomplishment that will give your son lasting rewards throughout his life (not to mention access to Eagle Scout scholarships!). 75% of the leaders in politics, business, and religion in this country are Eagle Scouts. This is not a result of "the old boy network", but because these individuals really learn out to motivate themselves and others, learn how to plan and execute, and learn how to participate and delegate through this program.