I am going on trip with my friends onat the weekend. I am going on trip with my friends at the weekend.

You could also say "... this weekend".

I am going on a trip with my friends onthis weekend. I am going on a trip with my friends this weekend.

"on the weekend" is correct but "this weekend" sounds a little better to avoid repeating "on"

I am going on a trip with my friends onthis weekend. I am going on a trip with my friends this weekend.

I am going on a trip with my friends on the weekend. I am going on a trip with my friends on the weekend.

We are going to go to Nagano in, Japan. We are going to go to Nagano, Japan.

We will enjoy driving , onsen and board games! We will enjoy driving, onsen and board games!

We will enjoy driving ,onsen, the hot springs, and board games! We will enjoy driving, the hot springs, and board games!

I'm not sure most English speakers know what an "onsen" is

We will enjoy driving , going to an onsen and playing board games! We will enjoy driving, going to an onsen and playing board games!