Only you can decide if you're comfortable riding the bike.

But as far is if paying more buys you more....yes. But how much you'll notice depends on your experience. If you're totally new to biking, you won't notice the difference between a $600 bike and a $2000 bike. What's different is the drive train and wheel quality. The more expensive drive train will shift smoother and easier. The more expensive wheels will be lighter and roll better.

If you're new to biking but are committed to doing it a lot for several years, spend the money. You might not appreciate the better drive train today, but a year or two from now when you're more experienced you'll be glad you have it.

If you've been biking fro years, it's a no brainer. Get the more expensive bike if you can afford it. You'll understand the first time you test ride. Go to the store and test ride a $500 bike (Look for Shimano Claris components). Make sure to do a lot of shifting on the test ride. Then test a $2000 bike with Shimano 105 components. You'll see the difference instantly. The low end components work and work reliably. The high end components work better.

The $2000 bike will likely be much lighter than the $600 bike, but for the type of riding you're talking about weight isn't a huge factor. Railtrails don't tend to have big hills. Lower weight is a bigger issue when you want to accelerate fast uphills. That's where you notice a bike that's 10 - 15 pounds lighter. For cruising along at a steady pace on a flat trail....weight is almost a non issue. (Almost)