Should I join a political party?

I am an adult in my late 20s, and I live in the US. I have a job that requires finding clients and building a client base. To that end (networking), I am thinking of joining one of the major US political parties (GOP or Dems). For the sake of discussion only, assume that I am not interested in joining a third party (Libertarian, Green, Reform, etc.).

The political landscape near where I live is as follows: There is a Large City near where I live. Large City is dominated by Party A. I live in a suburb. Politics in the suburb are a lot more moderate, as the city council includes members from both Party A and Party B. The county I live in includes Large City and a few suburbs like my own, but because Large City takes up so much area, the county is also dominated by Party A. The state as a whole is moderate and power is divided between Party A and Party B people.

Personally, I am a moderate but my views more closely match Party B than Party A. However, given the right candidate and platform, I am willing to vote for/join either Party A or Party B.

So, my questions are as follows:
1. Given my job and my goal of networking, would it be a good idea for me to join a political party? Or would it be a waste of time?
2. If I were to join a political party, should I join Party A or B, given the political landscape I described? I am not currently thinking of running for office but may run in the distant future (e.g. 20 years from now, when the landscape may be very different).
3. If I join a political party and that party is not in power or falls out of power, would that reflect poorly on me? That is, would I be stigmatized as a member of an unpopular party?
4. How easy is it anyways for the public to find out my political affiliation, if I get one?
5. Any words of advice or personal observations you would like to share. (Please no general statements – GOP is like this or Dems are like that. But I am interested in hearing anecdotes like “One time, I went to a GOP/Dem rally and X happened.”)