My experience is that YOU have to know how to tow YOUR rig. Many tow operators will convince you they know - but shucks, why not insist they follow your rig's manufacturer's requirements.
We once got towed and the operator (nicknamed "Greasy" by his partner) was ready to lift the front of our motorhome using the fiberglass front where the generator is hidden as a point of contact as he raised the front end. Then, seeing the issue, he thought to balance the 30,000 lb motorhome on the front lift using some short 4X4 to get extra help...
Needless to say, I told him the front genny door can come off with just four bolts - okay - that was solved.
Next was trying to supply air to the rig so the brakes could be caged. Greasy was ready to run the line from his tow truck to the front cabinet convenience air quick-connect. Wrong - there are one-way valves that prevent the air from getting backwards through the system and to the primary air tank... So - I sent Greasy under the rig to the air dryer where there is a Schrader valve specifically for this purpose (and others, probably but that's how you get to air up the primary tank).
Thank God for the Camp Freightliner course DW and I attend years ago - we learned so much, including do's and don'ts.
2008 Phaeton 36QSH, Safe-t-Plus, Quadra Bigfoot
2017 Jeep Cherokee Trailhawk w/ flat tow wiring mod.
Blue ox, BrakeMaster + BrakeAway, diode lights and charge.