This is an older threat, but here's my experience equipping and towing my 2025 Yukon behind a 45' motorhome.
My prior towed vehicle was a 2019 Yukon. The 2025 install was a good news/bad new story. The easy bits were adding internal TPMS sensors to the wheels, despite being the 24" configuration, the remote battery cutoff and air brake unit. For the battery I used a RoadMaster solenoid kit, it actually disconnects the positive terminal, but achieves the required results. The momentary action push button mounts on the forward end of the lower trim around the driver's door ... close enough to actuate when sitting in the seat, but out the way to prevent erroneous activation. One of the reasons for the battery disconnect is to disable the column lock. Fewer things to reset when powering back on again, compared to the 2019 model, the mirrors and that's about it. The air brake unit sits under the radiator lower bracket and I found a way to install the connector on the front fascia ... tight to get to but I can also de-modify with the purchase of a couple of new GMC trim plates, if I need to. The not so good stuff included a more complex BlueOx baseplate install, with fixed positions for the electrical and breakaway units and powering the Yukon lights to replicate the coach's lights. I tried multiple ways to get into the main wiring system, without using those metal spade connectors which are a disaster waiting to happen. The 2019 used a sandwich connector which featured the necessary diodes and was truly plug and play. With the animated turn signals, etc the 2025 electrical system is more complex and no-one offers an aftermarket plug and play harness. I finally went with a light bar in the rear window, held on with a suction cup and powered wirelessly from a device mounted to the 7 way plug on the coach. I'm not 100% happy with this, but seeing I haven't made any vehicle changes, I can always revisit it later.
From a towing perspective, the Yukon follows perfectly ... no wobbling or pitching. It tracks great, not needing any additional steering compensation to clear obstacles when cornering.
