I would say your sentence has the meaning of #1.
Consider these similarly structured sentences with different meanings.
1. 내일은 친구 만나고 서점에 갈 거예요. => Tomorrow, I'll see a friend, and go to a bookstore afterwords.
2. 내일은 친구 만나서 서점에 갈 거예요. => Tomorrow, I'll see a friend, and go to a bookstore with him/her.
3. 내일은 친구 만나 가지고 서점에 갈 거예요. => similar to #2, but more colloquial and emphasizes the connectedness.
-고 connects two actions which are considered distinct from each other.
-서 implies the two are part of integral activity, so meeting someone to do something is typically expressed with -서.
가지고 makes this integrality even stronger because it denotes "with/using the result" of the first action.