brake pipes on camper trailer

Wrap the lines in split flexible conduit avail at Supercrap or other auto spares retailers.

Garden hose, split, slipped over the lines and secured with steel hose clips. Plastic electrical ties will get destroyed quite quickly.

Cascade
I used heater hose on my camper and had no need to use zip ties to hold in place and has worked well

Big Show

Try Braided lines or try to relocate the lies behind the axle as has been done on my camper.