Link some photos back to this thread, then the guys + gals can offer some friendly advice. There is enough wind and some rolling hills around Beantown that can make a single speed challenging.
The Grand Prix is 2nd in line to the Record for entry level Raleigh Road Bikes and is built with high tensile steel. They ride smoothly, but are considered somewhat heavy and rarely are worth more than $200 in pristine condition, unless it is a mixte. If you want to upgrade wheels and all, best to look for a donor bike, that has the components you want on it.
A donor bike by way of example, is a Raleigh Super Grand Prix I recently bid and won on ebay for about $120. I can use the barcon shifters ($40), the Raleigh pantographed crankset ($40), and the high flange hub alloy wheelset ($30), and probably resell what's left for $50 or more.