I've done two solo trips so far. My first solo trip in 2012, I splurged on the Beach Club, because I'd stayed there before and knew I liked it. I had such a great time, I decided to go back this year, but this time I decided to save some money by staying at Port Orleans French Quarter. It was my first "non-deluxe" stay, but let me tell you, I really liked POFQ and would happily stay there any time. As a PP said, it depends on your definition of "nice," but POFQ is pretty and comfortable with recently refurbed rooms, and it has the advantage of being compact and easy to get around. For me, the big advantage of BC is the walk/boat options to Epcot and DHS, but my experience of the bus service at POFQ was fine. Personally, I would not do a split stay (unless I was there for at least 2 weeks with an unlimited budget

).
As for the length of stay: In 2012, I did a 5 night trip, so I had 4 full days plus an afternoon/evening on arrival day. This year, I extended by one night/day, so had 5 full days plus pm of arrival day - that was really perfect for me. I felt like I had time to do everything I wanted, even spent some time at DTD, started 2 mornings at DHS, 2 mornings at MK, 1 at AK, did what I wanted at Epcot during afternoon/evening hours (including Soarin' and Test Track).
A couple of tips on money: I don't do the Dining Plan, so don't need a Disney package. Thanks to advice from the Dis, I signed up for the free monthly newsletter from MouseSavers and have used their link to purchase discounted tickets from Undercover Tourist. I've booked Room Only reservations with my
AAA member discount (I got 20% off POFQ this year), and Disney will often come out with Room Only discounts as well (got 35% off BC last year). I don't have numbers in front of me, but I know this year's trip came in under $2500 including plane tix. (I'm not from Iowa, but a similar distance to WDW.) I did 4 TS meals (including 1 signature), daily breakfast at the POFQ food court, and counter service for the rest.
General advice: Set your priorities, then go with the flow. If you are at MK and craving Epcot fish & chips for lunch, hop on the monorail and go for it! (Been there, done that.) Don't be shy about solo TS dining, and don't be shy about meeting characters. (I've preordered the PhotoPass CD both trips and been glad of it.) As everyone will tell you, the biggest joy of going solo is the freedom to do what you want when you want. I'm already thinking about when I can go back next year.
Oh, one more thing: I swear by the Park Hopper and wouldn't go without it. If you think you don't need it, however, that can save another bit of money.