My basic utility rover which is very light, does not need sunlight and very stable even at speeds like 20m/s: It has 2 slots to transport kerbals to points of interest: To make the look like they are sitting is very hard, since you have to block them so they don't "wander up" the ladder while driving, so the way to get on is from below which has to be free. Also, adding them on top is very impractical. I build it especially that wide and long because you need that if you want to be able to move in a decent speed. This is not what you requested but what I found has proven to be the best thing to move kerbals around without using fuel.