To anyone wondering, you can jump between crates without squid form. It is actually pretty neat to get around with/run away, I don't think many people realize at the moment that you can do this.
I feel like a lot of people thing this stage is badly designed but it's really not. Awareness is so key here. While long range weapons generally are what dominate, they can still be countered by clever use of the halls. One thing about this stage is that you can see the enemy down a huge lane, and weapon fire around corners. If you can't challenge that, don't rush them head-on. You kind of have to focus on creating a path, blocking them in, and watching behind you at the same time. Also grenades and mines are very nice as you can punish those camping on crates (remember that unless they're on the truck they can't go into squid form to retreat, they must run in inkling form) as well as surprise/trap people around corners.
To the camping: you can't get camped here if you actually have a team. There is the main ramp and two halls to either side which are very dangerous for the enemy to go into/chase you into. They also allow you to bypass anyone there completely with like, 2 (3 maybe) potential exits. If they have somehow taken your two exit halls then you have other problems imo.
What else...there are plenty safe spots for beakon too.