I imagine Roger has a wish-list, of decreasing focus -- or at least this is what is a likely order in terms of desirability and to polish up his career resume.
1. Wimbledon - he wants to break his and Pete's shared record, and of course Wimby is the first among equals of Slams.
2. US Open/French Open - the French would probably be second because he only has one title, but he realizes it is a real long-shot and the USO is more possible. Either way, Slams are what he wants most of all and either would do just fine, if slightly less wanted than another Wimby.
3. Number One - in some form or fashion, even if it is just for a week. He must think, how cool would it be to rise to #1 at this stage of my career? Agassi is the oldest to do it at 33. YE1 would be nice, but I think just getting back to #1 would be more important.
4. Olympic Gold - Probably very unlikely at this point, as he'd be 38, almost 39, in 2020. But he probably still hopes he can somehow win it.
5. 100 titles - maybe he doesn't care about this, but the numbers fetishist in me thinks "100" is a nice round number.
6. Missing titles - Monte Carlo, Rome. I don't really think these are on his wishlist anymore as he probably won't play in them, or maybe only one, but I mention them because they're probably somewhere in the back of his mind.
There's probably a big drop-off between 2 and 3, and of course an overall goal of staying healthy, playing well, and winning more titles.