Seems you still can.
Tickets for most games can be purchased on arrival, unless specified in advance on the clubs' websites.
Head to Ticket Office 1 to buy your ticket, or collect pre-booked tickets from the blue collection booth outside Ticket Office 1. You can also pay by card or cash on the away turnstile.
Away fans are accommodated in the Lords Builders Merchants Stand behind one goal, with a total capacity of 1,800 seats. These are all under cover, with no restricted views.
https://www.wycombewanderers.co.uk/fans/away-fans-guide/