Todd- I have found that I am definitely more tired the first time I push my body to a new mileage high. Once I maintain the mileage, though, and especially once I reach that mileage on the next race cycle, I feel much better. So yes, it will get better and is normal. If you can build up to 10 mile days, do it, but don't get yourself injured. Then, do a good taper and you should feel energized and confident for Ogden. More miles (and tired legs) now will result in better race times.
As for taper- there are lots of good discussions at these links:
http://fastrunningblog.com/forum/index.php?action=search2 I would suggest a 2 week to 10 day taper if you aren't injured. Ask again once we hit May, if you want.