I went from 170ish to 205 (lean) on fruit and meat...

You were probably gaining actual muscle.  Destor's quick 7 lb gain was probably about 2 lb of glycogen along with the associated bound water, as expected when carb loading.

Oh I also upped my meat intake big time, and cut back on walnuts.

And don't try to slam my dedication, Wlfdg.  My diet and exercise has been controlled for almost 3 years straight now.  I work my ass off every day to eat properly and work out.

I'm after two things, results and performance.  I did the fruit bulking thing a try for 3 solid months, it did little for me.  I'll give this a try for another 2 months and we'll see which has resulted in more real muscle gain.

I have never weighed over 145 though, not even when I was on a diet full
of pastas, grains, and far more carbs than I'm eating now.  I'm willing to bet that I have already put on more real muscle than I did in 3 months of fruit bulking.

Remind me again, does your GF do Paleo?

At home I do all the cooking. So at home she eats Paleo.

I'd really like to be able to keep getting stronger without increasing in size from this point on.

Non-eccentric training. 

I totally get where you're coming from Destor, at 170 I honestly felt frail. I gained the weight over almost year though, it wasn't quick.

The weightlifting/bodybuilding world probably disagrees with me, but I think the most important factor is lifting big weights fast, and lifting bigger weights as soon as you are able.

I kept it all pretty simple, the whole 5x5 thing, but as soon as the sets/reps felt even slightly easier to do, I added more weight. Every single workout was uncomfortable.

And don't try to slam my dedication, Wlfdg.  My diet and exercise has been controlled for almost 3 years straight now.  I work my ass off every day to eat properly and work out.

I think the hard work over the past three months actually has paid off.  You said your weight varied by about 2 lb while on strict paleo.  Now, when you go off paleo and regain the glycogen and water weight that everyone loses when they start paleo, you're 2 lb heavier.  That means you gained 2 lb of muscle over the past three months on paleo, which is a respectable amount of muscle.  That's also why you gained a noticeable amount of strength over that time.

1lb of real muscle gain per week is very possible, it shouldn't take a year to gain a lb.

While a pound of weight per week is realistic, only a fraction of that is going to be muscle.  That's true of the 30 pounds you gained on your way from 115 to 145, too.

I've been there.  I was 120 lb throughout college, which was about as skinny as you were given I'm a couple inches taller.  The thing is, you can't be that thin and have a normal body fat percentage.  When I tried to take a skin fold at my waist, I got about as much as most people can get off the back of their hand.  By the Navy method, I was between -1% and 1% body fat.  I bet you were less than 5% at the most, which is very low.

Now, I'm at a normal body fat percentage.  Your pictures say you are too, even after dropping back down to 140.  That means a significant amount of your weight gain was fat - maybe healthy fat, since you're at what's considered a healthier body fat percentage now, but still fat - and some was glycogen and water weight, since you were making an effort to eat more.  At most, probably 10 pounds of that 30 pounds was actually lean muscle - which is still a respectable amount of muscle gain for one year.

The question is, what do you really want?  If you want muscle, that's going to be measured more in strength gains than weight.  If you just want weight, then quitting paleo and adding starchy carbs will certainly do it - but it will be more fat and water than muscle.

If you want respect - people asking you if you lift weights, for example, as sometimes happens with me - strength will help, but the biggest changes will come with things like improving your posture, and being able to look confident while still looking relaxed.

Well when I was 115lbs, I was skinny-fat.  I looked skinny (tiny wrists, arms etc) but my stomach held a lot of fat, my abs weren't even visible back then despite weighing so little.

Mine weren't either when I was 120 lb.  If you don't have muscle, you're not going to have muscle definition, no matter how little fat you have.

I still eat paleo.  My meals are meat, veggies, and fruit.  I added milk (which some people consider paleo anyways, I have no problem digesting it), and good tubers like sweet potatoes.

Sorry, but no one who knows anything about the paleolithic considers milk paleo; people didn't drink bovine milk until after they domesticated the bovids, and that didn't happen until the end of the paleolithic.  The same goes for the domestication of sweet potatoes.

Fruit bulking just wasn't working for one reason or another, and I put a LOT of effort and money into it.  There is no reason that I would have gained 0 weight in those 3 months aside from something lacking nutritionally.

Like any logical person would do, I'm trying something else.  If it doesn't work and I make no progress over 3 months, or less progress, then I'll switch back.

Obviously what you want involves getting the scale to move, and not just gaining strength.  And you're right, paleo may not work for your goals.  Maybe you need milk, maybe you need sweet potatoes, maybe you need grains.  There's nothing wrong with a nonpaleo diet if it paleo doesn't work for you.