I've not yet figured out how to get INT from the ENSYS event, it never triggers for me despite dozens of attempts. If you figure it out please let me know.
Yes the RPG campaign is several nights, I think it was about five. You can't repeat it to my knowledge at this juncture. There's another one (RPG campaign) when you spend time with Ayden as well, but that's a one-shot also.
Get combat armor (for your whole crew) ASAP, it's a real difference maker.
Have Enya fire a rifle instead until she gets up to about 70 where you give her an autorifle. Coilguns are exclusively for those with Ranged Combat of 85 or so, maybe 80 in the very beginning, in my army.
I'm not sure how repeatable it is, but the wiki says it's a 20% chance for the int increase. I got an int increase on the first try. I think 70 is the cap for it though so if you have more than that it probably will never give you one. Tried reloading and retrying a few times and didn't always get it but 20% is probably about right. I did buy the living room upgrade for it. I'm not sure if that's required or if it just makes it more likely. I'm hoping it's endlessly repeatable but I guess I'll find out. That was my plan for eventually getting to 70. Planning to raise my int to 70 via ENSYS exclusively if it's possible. Then I'll take the academy classes and read the books in case there's any benefit to having more than 70.
In my case I invited all 4 of my mercs to participate, bought all the refreshments available, had my 2 main slaves participate, and 1 or 2 other slaves work as servants. I didn't have anyone with low enough willpower to have them provide sex so I didn't do that.
Good to know the rpg events are 1 time only. I guess I'll save that for when I've got some girls trained up and all the house upgrades bought.
I had a feeling combat armor might be a significant difference. Planning on getting that soon. I started over with a soldier build to try a low int combat monster build. It's a lot of fun so far. Both ranged attacks and melee attacks are pretty effective since I have more than 60 of both in the first week without having to train it. Also seems like I gain melee and ranged skill more frequently during fights than the pure scientist build did.
One thing I'm also testing out that I'm not sure if it will work is a bit of a cheese strategy on the books. I'm buying up all the books and reading them til they only need 1 more session to complete and then saving them until I get my intelligence boosted. I'm hoping it does the int check on the last read but I guess I'll find out. I definitely got a message that I wasn't able to extract the full benefit from the book when I tried completing it with only 32 int.
I'm also finding manipulation an interesting option in place of charm. I started with 50ish manipulation but only 15 charm. So my charm pretty much always fails, but my manipulation succeeds pretty often and I get skill increases some of the time when it does. I can use that to reduce my slaves willpower on certain interactions. Probably not as effective as bondage but I haven't trained that up yet.
Once I get to crystal hills I can fix my charm but it's really expensive so I don't plan on using charm for quite awhile.