For those of us trying to level up before the season starts. What is a good way to get exp. quickly?

I know a lot of people are already level 155 and don't have this problem, but I didn't play this game much so only after grinding last night am I now level 113. I really want the M16 blueprint so I'm trying to get to 155 before the season starts.

I tried shooting down kill streaks in Ground War but it felt like even though I was getting a lot of exp., it was inefficient time-wise. I've been playing a lot of Shoothouse 24/7 since games are fast and the CQC allows for faster kills/objective taking.

Kill confirmed seems to be really good for exp. but maybe it's just because I've played it on Shoothouse. I feel like other maps will just be a camp-fest and I'm better off staying in that playlist.

Is Spec Ops worth it? Any advice would be super appreciated!