This was something I just made up now. I couldnt find my original.
Basically you wanna grab as many soil samples as possible, because thats the most difficult task. You can not get full value for transmitting soil data, even with a science module. And you can only hold so much soil per astronaut, per command module. Everything else is either unmanned, or can be transmitted at 100%.
I like to make sure I get as much data as possible from a single trip. So I've got 4 materials bays, and 12 of every other item.
4 comm arrays arent needed, I just do it for redundancy and weight balance. As ungainly as that thing looks, it will fly straight. Obviously the engines would go below. I didn't bother with that cuz it varies for each mission. Eve and Duna require a hell of a lot more fuel than Mun and Minmus, of course. I'd probably use little radial engines on each fuel tank, for landing, and moving to other biomes. The hard part would be conserving fuel so I could take off again and make it back home. But if something goes wrong I'd transmit as much data as possible before destroying the ship from the tracking center.
Solar power and batteries should generally be excessive. I find the added weight it usually worth it. RCS on the other hand is something that cannot be replenished and lately I've been ignoring that in favor of SAS modules, which are unlimited if you have batteries and solar panels.
That particular vessel could also do with some little colored lights. Theres tons of mod packs for such things and I highly recommend them.
Oh, and I guess a few big lights pointed straight down so I can land on the dark side of planets and muns.
I guess I could replace the cupola module in the middle with a satellite probe core instead.