You don't need gateways if you don't want to waste lvl, you can use 8 metal fence or 4 metal foundations and 24 metal walls, leave spaces of about 2 steps between each other, also place a few traps in different places nearby your escape position. And when you shooting hower above the ground, raptors may want to help for giga :)

Use smooth balm, it's not hard to get it from the lava cave