Good for you. Congrats
OK, a few comments:
Based on your answers....
You show strong interest in west coast resorts. That does in fact open up Worldmark (and others) as an option.
You show interest in Pacific, South American and Europe sites....that's good for RCI (and II) and having 2.5* expectations really helps.
Locked in school schedule: So, this answer indicates that you need to really research timeshares (and maybe rent some first!) before jumping into something that might not be a good fit for you. Peak week reservations during school holidays require either very good planning (12 mos) or lots of last minute flexibility (let's go to XXXX this weekend...it just popped open!). Rentals (including timeshare rentals) might be a better fit here....you should get some more insight on this.
3-5 days vs a week: Points systems (like Wyndham, Worldmark, HGVC etc...) tend to work well when you want to stay for more or less than a week. But, there are often restrictions about booking less than a week during peek demand at 12 months. On the other hand, you could easily piece-together reservations for 2-3 days at different resorts if you have more flexibility and can be flexible (read driving to the resort!). In your price range, Wyndham and Worldmark pop right up to the surface for flexible points-based systems.
At your price point, the higher end 4-5* resorts (Marriott, Hilton, Westin) are pretty much at or above your price point. But there are many 2-4* resorts that would fit the bill nicely.
In general, Wyndham or Worldmark are larger systems (with more resorts and availability) that offer good flexibility and reasonable pricing. Particularly, Worldmark has very good reservation, exchange, cancellation and booking policies that make it easy to book at 12 mos or on short notice--inside 30 days. Further, you can easily snag reservations in Asia and the South Pacific using Worldmark/Wyndham without going thru exchanges.
As always, I'd suggest getting input from other active owners in these two systems and get their opinion based on your desired locations and schedules. I strongly prefer Worldmark for a number of reasons, the primary reason is the ease of buying and selling Worldmark contracts at an affordable cost. I.E., buy it, try it, sell it if you don't like it. It's not such a complicated risk given the relatively low cost of a contract and the ability to purchase or rent more points as needed.
My number one piece of advice is: rent and visit at a few resorts that fit your needs and see if you like the system(s). Try before you buy. Plus, the rental cost shouldn't be too much more than the cost of ownership (especially during shoulder or off-season) and you can see what makes you and your family happy!
I hope this helps.