If I was to consider a used road bike what things should I look for other then size, and tire condition? I feel Im reaching my riding limit with my hybrid. Plus almost everyone else had s road bike it seems. If I was to meet a group or person to ride with I'd be trailing behind by maybe 5km /hr or more. I don't know a lot about cranks but but I think I'd like compact.
By far the most important thing when buying a (road) bike, whether new or used, is the fit. Everything else is secondary.
It can be difficult at first to figure out the correct frame size. You can use online fit calculators to get an idea of your approximate frame size. Most online bike stores also have some kind of a size guide that will help you get started. I would recommend a bike fitting, if you don't mind spending a hundred or two on it. It's not necessary and most people get started without it, but can save you both money and, more importantly, make the riding experience so much more enjoyable as compared to riding a wrong frame size. All of the above is based on the assumption that you're buying privately. If you have access to a reputable bike store that sells second hand bikes that is your best bet.
In addition to the frame size, you should consider if you think you'd be better served with a frame that has a taller headtube for a more upright riding position. There's been an increasing trend lately for these more gran fondo or comfort oriented road bikes as compared to bikes with a traditional race geometry. Given that this would be your first road bike, the chances are that you'd find a more upright riding position more comfortable. That said, if you're flexible there's no reason you can't go with a more race oriented geometry (that's what I did and am very happy with my choice).
As for wear items, tires are easily replaceable as necessary, but can add up to a hundred bucks to the purchase cost. A chain should last 5,000 kilometres or more, if properly maintained, but can give in less than a thousand if not treated properly. A cassette should last three times as much as the chain. The derailleurs and shifters and brakes should last much longer - some say 30,000 kms or more. This can vary, but my point is that if you can find a well maintained, low mileage bike, it will last you a long time without much worry about having to replace parts.
Re: cranks, compact 54/30 cranksets are almost a standard nowadays. Only the more expensive pro level bikes tend to come with a standard 53/39 crankset. Compact combined with a 12-28 or even 12-30 cassette should make for a hill friendly set.
You should definitely give road biking try. Chances are you'll like it and if not you can always sell the bike for a little loss.
