A few things.
Firstly being the derailleur - yes, seven speed works great for the bike but that rear derailleur was also on my lovely little Everyday Traveller cruiser. If any moisture gets into the metal castings or bearings (literally a puddle will do this), it will gum up and you'll have to replace it. Happened to me twice. I suggest something like a Tourney ($5 on ebay. Older but much better quality) or just something of a higher grade.
Avoid putting stuff on the bike that could get weathered, you want your bike to get you everywhere and not halt you on certain weather conditions (forget snow though). Lots of reflectors for night time, mudguards for wet weather. Avoid electronics (... too late.) and stay the hell away from fabrics too.
Other than that, it's a damn lovely cruiser, I've seen it around at local supermarkets before and it's an interesting bike for it's price.
Also get some forgetin' baskets for that pannier rack on the back! you can go on milk runs for your mom or something.
