The concept for the mod: You can make a mod that re-scales the planets in an ascetic format. Yes, it sounds confusing, but here's an example: You increase Kerbin's size to, say, the size of Mars. But instead of keeping the gravity at 1g, like some planet re-scale mods, make it to realistic scale (~0.3g). This way, the orbital velocity/the delta-v for LKO is the same a stock, but with Kerbin being much bigger and having low gravity. I know, it's easier done than said, so feel free to ask questions!