Hi - I'll be a P1 in the fall, but I've been a retail tech for almost 6 years, so I can comment on the retail side. I totally agree with bananaface's comment - the worst time of the year to get a tech job is probably the March-June time frame - we get calls almost daily then from students who just want to work in the summer. You might be more successful finding something in the late fall - early winter time frame. Even if you could only commit to a few hours a week at that point, you would at least get some experience and then you and your pharmacy could plan for how to get you more hours during the summer when you are off. I will also confess that I have a personal strong bias (having worked with all sorts of bad and good floaters, interns, new Rphs, etc. in the last 6 years) that you owe it to yourself to get some sort of retail pharmacy experience before you decide to go get a retail pharmacy job for the money. You really need to know what the retail setting is like - it's not for everybody, and I think it would be very difficult to be thrown into a pharmacy with your brand new license if you didn't have any experience beyond your 8 week rotation or however long your school requires.
However, I also agree with sdn1977 here - in many ways, there is more variety in practice settings within the hospital, so I think it is definitely worth working there some so you can see what that is like and what opportunities are there.