I've made a few attempts at sending a fuel depot to Eve orbit, though, admittedly, none of them has yet to get to Kerbin orbit. It suffers from a bad case of OMGTEHPHYSICS at various stages of launch and orbital insertion. For the longest time, the issue was the primary lift stage causing a massive stack collapse, as it dropped empty tanks, since with those empty tanks would drop the gigantic, egg-shaped mass of struts and girders that distributed the engines' force around the secondary (and almost entirely superfluous) lift stage. While I did manage to sort that out, the secondary (and almost entirely superfluous) lift stage has so much thrust that, without any of these structural outriggers of its own, its thrust causes a massive stack collapse.
Now, while I think I honestly could make this version of the Eve depot work, I'm probably just going to give it a rethink and redesign instead. This version was designed more with the goal of being giant and silly, while I was in a sleep-deprived stupor, so I think I want to restart with a more sensible foundational design, rather than continuing to use the current, tempermental version.
Probulator 1000 also carried out its mission around Jool, providing crucial information about the viability of solar power at that range. Apparently in the Kerbal solar system, the law of inverse squares is more of a law of inverse square-roots, at least with respect to light. With Jool about four times as far from the sun as Kerbin, you'd expect power output from solar panels near Jool to be one-sixteenth that of solar panels near Kerbin. In fact, output was only halved. This means that solar arrays are a lot more useful in the far-flung reaches of the Kerbal solar system than you'd expect, but not as great around the inner planets as you'd hope.
After carrying out that mission, Probulator 1000 performed a series of aerobraking maneuvers, only to find that you can't really use aerobraking to tune your Joolian orbit, the way you can with Kerbin. Because Jool is so huge, even if you don't go very deep into the atmosphere, you'll be in it for absolute ages. All the while, your apoapsis just drops and drops and drops. It's great for a capture maneuver, certainly, but if you try to drop your apoapsis below a couple million meters by aerobraking, you'll drop your apoapsis into the depths of the planet, even if your targeted periapsis is in the upper ten percent of the atmosphere.
Other than that, I've just done a couple of supply runs to the Hub & Grub. With the prospect of having a depot in orbit of Eve, I've come to the realization that I'll need to make a long-range oiler, and probably one with a bigger payload capacity, since multiple fueling runs to and from Eve would be a huge pain in the ass.
Anyway, loads of good SCIENCE! going on.