Can I leave funds in my stock account long term?

You can't receive payout until:

1) 45 days have passed since your first sale.

2) You have accrued at least $25 in royalty fees.  

If you want to wait until it accrues beyond $100, that should be no problem.  But I wouldn't allow uncollected fees to sit there forever. It's not a personal bank account you can instantly access.  It could take several days from the time you request a payout until you actually receive the funds in your bank account.

Can I ask why you want to wait?

I don't think there's a problem with allowing funds to accumulate beyond the minimim $25 payout level, but why would you want to? Adobe doesn't pay interest in these accumulated funds, so you're better off transferring them to your own bank account.