None of RSCRevolution's content is locked. Everything is free to all players!
The only place where there is a distinction between rscrevolution Classic's Free-to-Play and Members' content is made is in the Wilderness, which maintains a rotation system in order to allow for both styles of Player killing (use ::wildy to check rotation times).
Subscriptions only affect experience rates, along with several other perks.
You can check all benefits here: https://www.rscrevolution.com/store.php
The subscription tokens can also be bought from other players using in-game currency.