Confused Need help Newbie here looking for frist

Hello everyone. I am a single semi retired guy that will be doing most of my long distance travel in the summer I have 3 to 4 months off every year and me and my dog are tired of sitting at home alone. So nows the time to get a Rv so I will be ready to go early spring.

Now the question What the heck should I really buy. New, Used and if so how many years old. Motorhome, class A B or C , 5th wheel, tt. REg, light or ultralite.

There is just to many to chose. I have been studying this for 6 months now.
No matter how you look at it they all have good points and bad. The more I ask myself what I need the more confused I get.

I was leaning towards travel trailer or 5th wheel But now I am back to Class A or maybe C or B. Gas unit 30 ft range

My question is What are those must have things and what is the ideal size when it comes to small more remote campgrounds. I spend most of my time away from the big resort campgrounds.

Is there a Company that builds for the cold Canada winters. I live in central Ontario and will be mostly traveling in northern Canada.

Also I have heard not to buy anything over 10 years old is this true and if so why.

I am sorry for all the question I have tried to do the research myself but just find the more I read the more I do not understand

thank you