Rover power in KSP

Rovers are a nice gimmick, but unfortunately they are kind of useless from a gameplay perspective. Even the smallest moons are still far too large to circumvent by rover.

There is just one kind of mission where they are sometimes useful, and that are "Perform [experiments] on [planet] near [waypoint]" missions where all the waypoints are on the ground and very close to each other. Such missions can sometimes be done easier and cheaper with a rover than with a hopper. This seismic scan mission, for example, might be a candidate for an unmanned rover:

I don't know if you have done this. If you want to use a rover you could time warp and the rover will go 4 times as fast. The risk for accidents will be higher, but you can quicksave.

If you want to explore a planet fast a rover is not the best way. There are other ways that other people have described.

Das Valdez experimented a few days ago on his Twitch stream with a rocket powered rover.
While he did get up to over 100 m/s on the Mun, it was rather hilarious mostly because of the total lack of control at anything approaching those speeds (and thus the regular crashes and explosions).

I've myself created rovers that worked nicely at up to about 15 m/s, but higher than that and it's almost certain that you'll quickly lose control, flip, and either end up with a rover that's stranded on its back or explodes into its component parts.

Why use a rover at all then? Well, it's fun to putter around. And when searching for mining sites they can work well with the narrow band scanners. They can also be a good way to deploy mining drills. Create a surface base in a flat area near some slopes with high ore content, use rovers to drill for ore on the slopes and cart it back to the base where you dock with a craft that launches it into orbit to an orbital refinery (KIS and KAS can help here, docking rovers isn't the easiest thing).