If the main aim of the mission is to take the rib on the wheel, there's a slip at the wheel... Failing that Auchinstarry Marina has a slip too, and shouldn't be more than a couple of hours at "aux speed" to the wheel.
I have been toying with trip from Auchinstarry to the Canal Festival at Kirkintilloch (or on to the Stables for a pub lunch) for no reason other than to give the Aux a bit of excersise- as that is about a 5 (6 to the pub) mile stretch with no locks. The Festival Website hasn't been updated other than with the dates, so I'll post something nearer the time (like June!)
On the 2- stroke thoughts on the assumption that Automixers seem to run around the 200:1 mark at idle, is it worth putting a tank of "Premix lite" at say 100:1 (and a reminder on your wheel not to open the throttle too much!) in the boat for the long slow stretches?
Canal navigation guides are avaialble online.