While I don't know the local geography, is going the other direction (via Hume Hwy) an option? I just had a look at PlugShare - EV Charging Station Map - Find a place to charge your car! and it seems there are Telsa HPWC owners in both Wangaratta and Eurobin who may be able to help.
Yep thanks Chuq. I've got the Hume route via Wangaratta as my primary option at this stage, just investigating alternatives. I wouldn't take the car up through Hotham so would leave it in Harrietville if I went that way, so the Omeo route has the possible advantage of driving all the way to the house at Dinner Plain. Not certain yet whether the cons outweigh the pros as yet though (assuming the Bairnsdale charging option is even viable)!