We will drive from Chicago to Canada via Detroit. An overnight stop is planned on the Canadian territory but not far from the border.
So, I have two questions connected:
1.What point of the border crossing could you advise?
2. What place for a night stay would you recommend (we would prefer nature and silence)?
We are 2 families of 3 adults and 2 children. Our overnight budget is limited by USD80-90 per family.
Thanks in advance

Where you cross depends in part on where you want to endup in Canada.

On my trips to that part of the USA, I cross at the Ambassador Bridge between Detroit and Windsor, because it is linked to the interstate I want in Michigan.

If you want to be farther north in Canada, drive up to Port Huron, and cross into Sarnia.

BAK

My further destination in Canada is Niagara Falls

I would take I69 to Port Huron and cross to Sarnia. Follow 402 to London, then 401, 403 and the Queen Elizabeth Way to Niagara Falls. You should be able to find accommodation in your range in Sarnia.

This avoids driving through Detroit and the distance is about the same either way.

For wait times at the border check:

http://www.cbsa-asfc.gc.ca/bwt-taf/menu-eng.html

Special thanks to laverendrye for the useful info about the wait times!

I agree with Laverendrye ... Crossing at Sarnia is so much better. Less hassle... and 402 is a quiet highway, as highways go.
I'm not sure where to advise you to stay if you want quiet and nature. To break up your trip, you could stop at London.

If you travel through Sarnia, and are looking for somewhere kind of quiet and nature oriented for your overnight, this is about 20 minute drive up the lakeshore and is a really wonderful place. They have a B&B and you could check on whether they could accomodate you.

http://www.forestglenherbfarm.com/m_bedb.html

Thank you very much.