Disregard grids, acquire theater of the mind
Today, with PF1.0, you can easily play without a grid.
For example, my groups play with miniatures and decor features. If we're in a dungeon or a building, we usually use Dwarven Forge terrain, so there is a grid built in. But when we play in the forest or on hills or generally outside, there is no grid, and we measure movement using a sort of ruler marked in grid-equivalent units. Sure, there is a "fudge" factor involved, and it gets harder to adjudicate weapon reach, 5-foot steps and so on, but it's doable.
And you can certainly play "theatre of the mind" PF games with no grid, no map and just vague descriptions of placement and distances. But IMHO you lose some of the tactical elements of moving figurines around on the battle map that I enjoy.
I don't see PF2.0 being any different, especially considering the inclusion of a grid-based map-pack in the playtest materials.
We've never played Pathfinder on a grid, aside from the occasional special battle, and we've never felt it needed it. Sure, it takes a little work for the GM to keep track of who's moved where, who's adjacent, who's flanking, who's got reach, who's sixty feet in the air and screaming etc, but it works just fine.
The game will be made with the grid in mind as a default, but you have the option as always to not use it.