Hi Jimmy B and welcome. She is a georgeous looking looking girl. I'm in the same boat as you with a larger breed dog who is nearing 13. If you live near the beach that's some of the best exercise you can give them, swimming. Easy on the joints.
I agree on keeping the weight down and being from Tassie myself i know how cold it can get here ( snow on the mountains around my place today), so having some where warm and comfortable off the cold ground for them to sleep also helps.
If you think dogs can't count, try putting three dog biscuits in your pocket and then giving Fido only two of them. ~Phil Pastoret