I tried doing that too.
But, Juni kept "disappearing" on me, and forced me to restart too many times.
So, now I just do maybe two mission between Juni's Mission to make sure I don't make "too much" money in between...since I think she disappeared because of my cash level, they seemed to be connected somehow.
And no, leaving the planet I was to meet her at and returning didn't make her show back up, nor did restarting from a slightly earlier save (unless it was one from RIGHT after the last Juni mission, which I didn't always remember to make a save at. *hangs head*).
I am still having a lot of fun with it though.
I play SP during the day, when I cannot connect to the internet due to being on dial-up and not wanting to tie up the phoneline.
And I play MP ALL NIGHT! In fact, I am ingame right now, with it minimized! hehe
Even with it's small flaws/shortcomings you HAVE to admit this game ROCKS and is JUST the shot in the arm the genre needed!
Fly well,
Pyrate Dredd