My first interplanetary landing was on Ike (career explore mission) and I managed to land on an ore patch without a survey. I thought "this is cool, I'll fuel up, hop over to Duna, get the science and come home" .... this was a stock install with no mods so I didn't know how much TWR or DV I needed. In the end I just made orbit and pushed all the way home with the EVA jetpack. I think it took 6-8 hours IRL even with a lucky Mun assist. Now I use Kerbal Engineer Redux and research new destinations.