I'm looking forward to being there with you, too.

Your suggestion about the rock concert lookssounds like a great idea.

suggestion is the noun, suggest is the verb. We also use "sounds like" when you're in conversation with someone who suggests or describes something. ie "it sounds fun".

I don't usually do exercise, and going climbing could be too hard for me.

You don't need "do" before exercise. Exercise as a verb is not something that you "do" in this sense, unless you're asking a question ie "Do you exercise?"

By the way, I remember we went to dinner at a super mb Mexican restaurant the last time, but I don’t remember the name.

need the preposition "at" before a dinner. Also, capitalize "Mexican" because it is technically a proper noun.

I'd like goingto go again if it's possible.

You need the infinitive version of "go" because you already have "like" to introduce it.

Your suggest about the rock concert looks a great idea.

suggestion* and adding “like” after looks would make the sentence flow better.

Do you know I mean?

Do you know *what* I mean

I'd like going again if it's possible.

I’d like to go again if it’s possible. “Going” means you’re going to that place already. You can use “go” as in you want to visit that place again. And make sure you add “to” too connect the words.