Lee wrote:

I've started to finalise my route as follows, haven't decided on
places to stay yet because I need to decide on my budget:

Sun - Arrive 17:00
Sun/Mon - Toronto
Tue/Wed - Niagara Falls
Wed - Nr Toronto
Thu - Nr Algonquin
Fri/Sat/Sun - Ottawa
Mon/Tue - Montreal
Wed- Nr Kingston
Thu - Nr Belleville / Prince Edward
Fri - Toronto (Meal booked at 360 restaurant)
Sat - Depart 19:00

Any thoughts on this?

Just a few thoughts. Niagara Falls is about 1 1/2 drive from Toronto.
Rather than spending 3/4 of an hour to get to a downtown hotel, getting
settled, unpacking and then having to pack again, go directly to
Niagara Falls and get the travel out of the way. That gives you a travel
free day in Niagara and saves the hassles of checking into one more
hotel.
I am not sure of the advantages of visiting Kingston and Belleville,
but there is an interesting air force museum in Trenton.

There are some nice resorts in Algonquin, but they tend to be quite
expensive. You migh consider grabbing a hotel in Huntsville, which is
about 25 miles from the park. It is beautiful in Algonquin in September,
so long as it is not raining. If the weather turns foul you might want
to scrub that leg, though the drive up from Orillia on is quite
scenic. Just as a suggestion,. you might find it interesting to swing
over by Midland and see Ste. Marie Among the Huron.

Montreal is a nice city and one of the most economical cities to visit
because there are lots of good deals on hotels and you can get great
meals for very reasonable prices. All in all, it seems like a lot of
driving over a short period.of time. If you spend extra time in
Montreal or Toronto you can skip Kingston and Belleville. Perhaps you
could just get an early start and stop at those spots along the way. It
is a 5-6 hour drive from Montreal to Toronto.