I like the idea of going East if you choose not to join up with experienced hunters on the Westside. Blacktail are notoriously hard to see in the bush, and take a trained eye to find in clearcuts. Klickitat units have a three point restriction, which limits success for a newcomer. You should see some deer there though, which may not be the case on the westside.
The main point should be to enjoy your time together in the woods and hopefully get to experience the thrill of having a chance at a shot on a deer. Next year, if your son's age allows, you may want to apply for a youth tag in Spring so that he can take a doe (if selected).