My experience with turtle mode is it's basically to get you off to the side of the road, not much more. I got it once very near home while testing and was only able to go a long flat block at 5mph followed by coasting down a slight hill but was unable to make it all the way up my shorter driveway. I ended up having to run a 50' extension cord and use my 120v EVSE to charge it up enough to drive into the garage where I could use my 30a L2 EVSE. Unfortunately, I had to charge for several hours @ 120v to give it even enough power to turn it on and move the 30' slightly uphill to get to my L2.
Long story short, don't expect really any range on turtle and what you do have is slow on the flat and almost nonexistent power for a hill.
2012 SL purchased used 2/'16
2013 S w/QC purchased new
Juicebox Premium 60a L1/L2 EVSE, Ebusbar 16a L1/L2 EVSE
'12 EVSEupgrade'd 20a L1/L2 EVSE, '13 EVSEupgrade'd adjustable 6-20a L2, 6-13a L1 EVSE
Zencar 13, 20, 30a L1/L2 portable EVSE
GE Durastation 30a