The 52T chainring using a 1/8th in chain works, but you'll have to sand/file off a bit of the derailleur otherwise the chain will rub against it. Also, if you use the purple ebay crank, you'll have to be careful of the guard, which will get in the way of the smallest cog. You will need a 1/8th inch chain instead of the standard chain, although I think one package of chain is enough, I added a few more segments just to be safe.

The Schwinn Loop 7's stock hub uses a freewheel and can not use a cassette. With 52T and the stock freewheel, I found it to be pretty comfortable with a pretty wide range for both climbs and not spinning like mad on even terrain.

I would not suggest the triple in the front without a derailleur. I've done something similar and had a bad experience with it.