One: If you have to go the "Flash Drive" route like a cave man, you can always save Pages documents as a Word file... so if you have to use a PC later, you're covered.
Second: Save your work to iWork for iCloud on iCloud.com, then sign in to Pages for iCloud on any Mac or PC at school and go from there.
The Nexus 4 has a 2100mAh battery. The Nexus 5 is 2300mAh. Not exactly a huge difference. Seems like reviews online are stating the Nexus 5 battery life isn't that much of an improvement over the 4.
"With Wi-Fi turned off and LTE activated, the Nexus 5's 2,300mAh non removable battery has a reported talk time of up to 17 hours. When both are activated, Google says, the device lasts 300 hours on standby. Internet tests reportedly yielded 8.5 hours on Wi-Fi and 7 hours on LTE.
While our handset is still undergoing battery testing, preliminary observations show that with brightness levels cranked all the way up, the phone streamed an HD video on LTE for approximately 20 minutes and lost 13 percent of its battery life." - CNET
So, if you pay $700 to pay off the iPhone, and $399 for the Nexus, you're gonna be roughly $1200 in the hole, after tax and shipping. With an AT&T locked 32gb iPhone 5S in Space Gray, you can maybe sell your iPhone for $600 to $700... give or take... minus shipping, and any eBay and/or PayPal fees.
Worst case, you end up paying the $399 (around $500 after tax/shipping) plus the difference from paying off and selling the iPhone, maybe up to $100... so the Nexus 5 is costing you $600. Not including whatever payments you've already made on the iPhone 5S.
In short, if you don't like your $399 32gb Nexus, you're going to have to sell it, maybe for $350... leaving you down around $250 when all is said and done, and you'd have to buy another iPhone 5S. If you bought another Space Gray 32gb at full retail, you're looking at $750 before taxes. After factoring in taxes and the residual loses from your Nexus 5 experiment, you'd be $1,000 in to get back to the iPhone 5S, which you already have right now.