This post was about having Whis train you in Adventure Mode, but I've edited it after my recent findings, which are below.
Edit: I've found out that spamming the potara script is kinda broken in adventure mode. Basically, I used DFHack to get 2 earrings made of Potara, an inorganic material. I'm pretty sure all you need is an item made of Potara in your inventory to fuse, so I bodyswapped with a nearby farmer and had him grab the second earring. I went back to my original adventurer, entered the dragonball/potara in DFHack, and.. didn't fuse. I tried wearing the earrings too.
I'm still kinda confused about it, but it appears the potara fusion script increases your stats... exponentially. I went from only being a Super Saiyan, and after inputting the script 3 times, I got to Super Saiyan 2. However, I never actually fused with the farmer who also had a potara earring. I decided to keep spamming it, and..
"Hello, (name). I am Whis, attendant to Lord Beerus the Destroyer. I've been watching you with interest and have decided to offer my teaching to you in god ki."
This confirms that Super Saiyan God is possible in adventure mode, and after accepting the request I immediately learned SSJ3, SSJG, and SSJB. Pretty sweet. Sorry for how long this is, I wanted to tell everyone else who was curious about Potara fusion, Super Saiyan God, and increasing your stats quickly in adventure mode. I do *not* know if the Potara earrings are necessary to increase your stats.