As long as you sanitize the hop bag and anything else that'll touch the beer (minus the hops themselves), you'll be good.
I like the 5-7 day dry hop plan...but leave the brew in bottles for longer than a week or 2. Minimum 3 weeks, but try to resist opening them for another 1-2 weeks after that...you'll appreciate the improved flavor the longer you wait. 1-2 weeks just isn't long enough for carbonation and good flavor maturation.
"Just chug a few. Then all of the sudden it's time to be drunk, and you don't have the time for whatever else you were doing." -TallDan