Where do folks take TT for brake check?

[Sport165]

Hi,
My little travel trailer is just about ready to hit the open road! The last thing on my list is the Brakes! I noted when the tires were changed, that the drum was a little rusty looking but I think that's just normal? Please let me know if it's not, picture below...

Anyhow, about the brakes, the trailer doesn't have more than 9-10,000miles on it total, but because it has been sitting for the last 6 years, I'm thinking it would be a good idea to get the brakes checked? Possibly they may need to be adjusted?
(Just thought of a question about the runaway trailer brake switch? I noted a very tiny black box attached to the side of the trailer with wires, and there is a wire cable attached to this, I realized this is the runaway trailer brake box? Where exactly do I attach the cable? I thought it was attacged on the hitch locking pin, so if the trailer became unhitched it would pull on the cable which would activate the trailer braking system through that black box, but somebody told me I'm supposed to actually put it on the tow vehicle itself?) (Now I'm confused & just want to make sure I have it in the right place!)

Keeping in mind I'm relatively new to the travel trailer world, & the whole maintenance issues ETC that come with getting one ready for the road,---
The big question is, where do I take it for this type of thing? There is a camper world about 30 miles from here but I was wondering if I can just take it to a regular automotive type place? Or does it need to be somebody who specializes with travel trailers?
Thanks so much!!

[DMRGMC]

Each fall season I take our 5er to the Garage that has serviced our vehicles for 37 years. They have worked on all 4 of our Rv trailers. They service and adjust the brakes, balance and rotate the tires, check, replace or re pack the bearings as required. They don't have the room to do it inside so I drop off the unit and they get right to it. They have installed shocks on a previous 5er that they sourced, they have also checked the axles to make sure they are aligned. I trust them totally. If they couldn't do it for some reason there is a company locally that specializes in all non Rv type trailers and accessories that I buy towing stuff from, hitches etc, that I would go to, they have the room to do it inside.