I use to pull my 1999 Jeep Wrangler all the time behind my truck. I just left the steering locked. Never really ever noticed any front tire wear on the Jeep. Probably not a good idea however.
It is not good at all running down the battery below it 50% charge state. Even for the non-deep cycle start batteries.
I guess you could install a battery ON-OFF disconnect switch or just pull the negative battery cable when being in tow.
I pulled my truck negative cable once for a few days when I had to replace my alternator. When I got everything up and running again I had lost some computer settings by not having the battery connected all the time. The manual said this was normal and it would relearn itself after using it for awhile. My idle was so low it would stop the engine at stop signs. After a week of one foot on the gas pedal and the other foot on the brake I finally took it back to FORD to get my idle setting reset. Cost $90 for two minutes of work on their computer console. Don't you just love these electronic sensors. No manual idle adjust anywhere to be found.
Roy Ken