How far can you go into the enemy’s homeland? When are you kicked out of each tier? What is the chicken mechanic? Look within!
As far as you’d like! However, if you are more than 2 levels above the end of the tier (every 10 levels, so levels 12, 22, and 32, with no lockout for Tier 4), you will be turned into a chicken with one hit point and the ability to fiercely peck your opponents for an incredible amount of… one damage, in melee. Let loose the flock to peck a low-level person to death with a large guild assault! You are turned into a chicken only if you perform an action on someone who is RVR flagged, such as healing someone who is flagged, or attacking an enemy. The other way of course is to flag yourself with the dropdown menu on your character’s portrait.
Assuming you aren’t chickened due to being too high a level for that tier (Tier 1 will make you a chicken if RVR-flagged at level 12, Tier 2 at level 22, and Tier 3 at level 32), you can go as far as you’d like, other than major towns that will have guards far too powerful to deal with. You can go to an enemy’s Public Quest area, roam around their PVE areas (in fact, some Public Quests encourage RVR action by setting the two sides to accomplish opposing goals to trigger the second stage of it for their side!), and attack anyone who is flagged freely. Of course, they don’t have to flag themselves, but many in the beta at least have opted to flag themselves for some spontaneous RVR, especially if they see an enemy flagged near them.
You can attack people who are flagged near some of the lesser towns, though you shouldn’t try to follow them inside as there are a couple of high-level war guards stationed at the inside fringe of them, as well as normal-level guards. You typically can damage them if they don’t go past the border of the town, however. There are no artificial restrictions on where you can go inside a given zone, and in fact most zones are set up to have the PVE areas of each pairing adjacent and cross over at points in the same zone. If you are lower than around 2/3 up to the top of the Tier’s chicken level cap, you gain a buff automatically when RVR flagged in an RVR lake or Scenario that boosts your hit points and stats to the equivalent of what you would have at the 8th level in a tier. While it does not give you access to higher-level abilities than you can already train, it makes a significant difference in the experience and allows for those lower in the Tier to participate. The “Bolster” levels that this affects your stats up to are Ranks 8, 18, 28, and 38, for Tiers 1, 2, 3, and 4 respectively.
Finally, there are also “RVR lakes” which are mini-frontiers with a Keep or two plus a couple of Battle Objectives, which becomes larger and more complex with each successive zone in the Tier. Some of these “RVR lakes” span across the two zones of a Tier, i.e. the east end of one zone and west of another, and are connected physically. These areas are outlined in red on your map, showing the area that is designated for them. These are full-fledged versions of what Tier 4’s RVR will be like, and provide an excellent training ground and taste of RVR action earlier than the top level. Thanks to the chicken mechanic, you don’t have to worry about a Rank 40 coming into your Rank 12-21 zone and demolishing everyone. Each side has a Warcamp far away from each other, which is guarded by a hefty contingent of powerful NPC guards plus siege weaponry to prevent spawn camping. They’re usually around equidistant from the central Keep, and each side is usually a little closer to one Battle Objective than the other, with the other side being closer to another.