Probably not joining, but succession games that aren't vanilla are just... too easy. The only time that rule doesn't apply is if the mods specifically make the game harder (deadly re-entry and such, but all the *good* mods that make games harder need another mod, like FAR that makes it easier in some aspects). The biggest problem with vanilla and not having engineer is that people refuse to take things slow. It's entirely possible to figure out how much dV is in a rocket using math and values the game gives you, and as long as you plan nodes out and don't try to do things on the fly it's not that hard to get to duna, land, and come back before you have even researched the larger rocket stages... all on vanilla.
Poll
