I can't recall what bike you ride, but I think it's easily doable in one day especially if you're doing a sunrise to sunset ride. Last year a group of us did a
Summer Solstice ride which went out to Calabogie as well and these long days make it very easy to do. Bring a hydration knapsack if you can, don't eats any big meals and it will help with staying focused for the later parts of the day.
I made some changes to your route if you want to consider any of them.
I removed the 507 and replaced it with doing Lower Faraday, the 504 from Coe Hill and Northey's Bay Rd.
Also added in Flinton Rd and over through Myers Cave, so this way you minimize time on Hwy 7. You are also now taking the 511 and Centennial Lake Rd, both of which are highlights of the Calabogie area.
goo.gl
Be careful on South Lavant Rd, it might be in really poor condition heading towards the 511.
If you think you can handle adding more roads in, then take the 514 up to Old Barry's Bay Road, then come down Siberia Rd - something like:
Queen St S to Streetsville
Some of us will be going out that way for another Summer Solstice ride this year, so post up how the road conditions are!
Safe ride!