I've had the game for about 5 years. I don't think I bought it before the date that I get the free expansion, but I got it pretty close after that. I have posted under another name, and lost that log in and have not posted here for a couple of years.
Anyway, after 5 years..... I finally landed on Duna and returned to Kerbin. With several "refueling" stops at Ike to power the journey home. I took 3 kerbals (pilot, scientist, and engineer) with me. I got 4000 science from that trip by restoring the science modules and of course making sure I took science from every biome I hit.
It took several hours, maybe at least 10 in playing time. There were a lot of restarts because of some kind of screwup .... with the design or with decisions I made along the way.
But, I made it!!