Hi RMED, Well we went in via the freeway, over by route 66 casino. There is a gas station called the 66 Pit stop. The entrance is just right in back of it. I will get more information on how to get in the other route, apparently the other entrance is in Rio Rancho. It is really cool there, you can go slow or get crazy, beautiful area.
*Side Note* We discovered that in the gas station they have a restraunt called Home of the Laguna Burger. It is a really small place, but we swear they have the best hamburgers ever, home made fries too. Would reccomend, they also have a really cool gift shope with lost of route 66 items as well as signs and posters from the 50's and lots of harley stuff. Check it out if go.
Heres a map I found on the web.