You can purchase your Go Las Vegas Explorer passes right in Sin City. 

Madame Tussauds Las Vegas

Address 
The Grand Canal Shoppes
3377 S Las Vegas Blvd, Las Vegas, NV 89109

Hours
Open 365 days a year at 10:00am.

Passes available
Explorer pass.

You are currently not able to purchase the BYO and All-Inclusive pass in Las Vegas.