If you want to stick below $300, don't look at any of the photos in Hoyt's post.

So, your initial post said "build", but you're looking at some pretty fancy add-ons. Are you wanting to start with a good rifle and build as $ allows? I just told my story in a recent thread, did the same thing and ended-up spending more doing it that way...but a budget is a budget. It's post #2 in this thread;
http://www.canadiangunnutz.com/forum/showthread.php?t=790983
If you're interested in any specifics about that gun (.22mag) just let me know. Now, I do like the robust-nature of the Boyd's laminate stock, the Savage accuracy vs. value, but this was my last .17 HMR, a CZ452 Varmint.
I post that NOT to say "get a CZ instead", rather, to qualify this next comment~I don't think a .17 HMR is a 200 yard gun. In regular field conditions (hunting very small game) maybe 150-175 yards. Will it shoot that far? Yes. If nice groups are your goal at 200, you might want to consider a centerfire rifle like .204 Ruger or .223, not to mention the punch they also deliver at those ranges. You can have a pile of fun shooting HMR, and marvel at the accuracy of it for a rimfire cartridge, but 200 yards is really on the outer edge of that gun's useful (=accurate) range. Again, my opinion. I'd say have at it, sounds like a fun build!
Scope~bigger isn't always better. Look through a crappy 24x power scope, then a superb-quality 9x scope and try to get a sense of what value better glass offers. I can very clearly see .17 holes @ 110 yards using anything over 12x. A decent 14x scope (at that distance, if your eyes are half-decent) will serve you well. The scope on my .22mag Savage (in that link) is a Mueller APT, 4.5-14x. To me, one of the best scopes (for the money) in that magnification range.
Lastly, if you're in/near Minden...Epps is about an hour from where you live and they usually carry a great inventory of Savage rimfires. They're also a CGN sponsor. Lastly (for real this time)...

.... The only guys I know personally who own .17HMRs don't know each other...but both shoot a Savage 9317 TR. One of them is a gopher-slayer of the highest order near Calgary AB, the other uses it here in Ontario for target shooting, the odd crow and/or groundhog.