First...as far as bringing beer into Canada from the US, bring as much as you like. There is no duty anymore, it is tax. If you add the tax on you are still way cheaper than buying in Canada. We go quite often over to the US. We bring back 4or 5 cases of beer each and pay the tax. We pay about $40 for 24,in Ontario and around 16 in the US, do the math. Alcohol is a different story, you will pay more than twice in tax what you paid for the bottle.
We travelled all across Canada. We never get tired of travelling through northern Ontario. The trip from Wawa to the Sioux is incredible. Make sure you pay attention for the last gas signs. There is quite a stretch without any. Sudbury is very hilly. You could come down from Espanola to Manitoulin Island and take the ferry across Georgian Bay to Tobermory, then hwy 6 south to the 401 east if you want to add something different.
If you travel across from Wawa to Timmins and down to North Bay it is a totally different route. The highway down to North Bay is boreal forest, small lakes, very pretty. Timmins to Toronto with trailer around 10 hours.
You could also take the northern route from Thunder Bay across to Kapuskasing #11 to Cochrane and then down to North Bay. It is a wonderful drive. Kapuskasing to Toronto about 13 hrs with no trailer.
North Bay to Toronto about 6 hours. We pull a 27/30' trailer. We travelled from Timmins down to Toronto this year. We managed to stay with traffic no problem. Barrie to Toronto will be the worst of the trip. It is not far but very busy. Try not to head south on a sunday. It can be bumper to bumper, people heading home for work mon from the Muskokas, the heaviest cottage area.
Once you are down to Toronto on the 400 and take the 401 east to Quebec it is no problem.
Travelling through Montreal can be hectic. Give yourself time and signs will likely be all french if I remember correctly. Contrary to many opinions, we have never had any issues with communicating with people in Quebec.
I give you travel times etc. to travel from area to area but it would depend on what you want to see and traffic. The ones I have given are what it usually takes us.
Old Quebec city is a must. Find a spot out of the city to camp and drive in. Taking the RV in would be crazy.
The maritimes are gorgeous. I could give you the list of places we love.
We travelled back to Ontario from New Brunswick through the States. We crossed into Maine. The trip that way home added to our journey, it was great. We added an extra week in doing so and that was not seeing as much as we would have liked.
Highways are good. Like all of Canada though, construction in the summer, LOL Most of the ones until you hit North Bay will be 2 lane with the odd exception of 4 lane.
One thing for sure..reserve! In order to get a spot in Ontario and down east reservations are a must. Go online to Ontario Parks and you will see you can reserve from around 4 months before arrival date.
You will get many opinions such as mine. The trip will be yours though. Do your homework as you are and by asking people you will find many interesting places to visit.
Good luck!