Assuming a party of PCs(Level 1) would be banished to a plane other than the Material Plane, which planes listed in the DMG would be the easy to survive on for those players?
Assuming, of course, 'survivable' means the plane(or planes) provide breathable air, food, water, and shelter(for 8 or more hours). This requirement(not Survivable requirement) also includes natural wildlife, such as [edible] creatures, [edible] plants, and monsters. These creatures, plants or monsters may or may not have hazards. The land may also have optional hazards.
The possible planes listed in the DMG are the Astral Plane('Starry Plane'), Ethereal Plane('Interlapping Plane'), Feywild('Fairy Plane'), Shadowfell('Shadow Plane'), Elemental Planes('Planes of the Elements'), Material Plane('Plane of the World'), Outer Planes('Planes of the Gods/ Demons'), the Outlands('Plane of Gates'), Sigil('Plane of Doors'), Demiplanes('Plane of Extradimensionality'), and the Far Realm('The "Unknown" Plane).
Best Answer
Feywild
It seems that the Feywild has everything necessary to live there because it has
and
and
which also indicates that someone could live there. There are definitely dangers as well. It is also called a place of death and is cited as potentially causing memory loss.
Parts of the Inner Planes
The parts of the elemental planes closest to the Material Plane are similar to that plane while the parts farther away become more and more hostile. The better parts of those planes seem reasonably easily survivable. There are earth motes on the Plane of Air, many of which have lush Vegetation. There's also mention of breathable air and even water in some parts of the Plane of Fire. While the information is incomplete with regards to the things needed for survival, the information that is there definitely implies that the regions close to the Material Plane are reasonably hospitable.
Some of the Outer Planes
Information concerning the outer planes is sparse in the DMG but for some of them we can assume that they are hospitable.
Mount Celestia where travelers can let down their guard. It also has an optional rule very beneficial to the players.
Bytopia, also called Twin Paradises, one of which is a pastoral landscape.
Elysium which is a welcome refuge for planar travelers. The optional rule however makes characters unwilling to leave which may be a problem.
The Beastlands is wild nature. There's definitely food but it's not without danger, the optional rule may turn characters into beasts.
The other Outer Planes are much less hospitable.
Alternative: Demiplanes
Demiplanes have
and can be pretty much anything. You could therefore have a demiplane that fits your plans for the adventure.