Aw Jayne, I'm so sorry to hear about Zac, we lost one of our boys recently and I know how hard it can be, especially for gliders left behind

You've definitely come to the right place though, this board is full of people who've kept gliders for years and years, and has a fair few very responsible breeders on as well so hopefully Tilly won't have to stay lonely for long!
In regard to advice for a lone glider, taking her out as much as possible is definitely the way forward, I also use a heatpad under the nesting pouch to keep her warm at night as they have no one to cuddle, and I also treat her more than I did before -a couple more pine nuts or mealworms here and there is always useful. I also ensure that my girl (her name is Maddie) has something which smells of other gliders with her, as this can help them feel less lonely. Ultimately the most important thing is to find a happy healthy glider as soon as you can, as there is only so much you can do for her.
Welcome to the forum, and I'm sorry it's under such sad circumstances!!
xxx