Question about the logistics of surveying, clearing, fencing acreage

I'm trying to put this all together in my head while we're in the early stages of buying 20+ acres, mostly wooded (so I haven't talked to any of the guys who will be doing the work yet). The land had a recent survey, but the only markers to my knowledge (according to the plat map) are at all of the corners, some of which are over 1,000 ft. apart (and the property shape is irregular - not a perfect square or rectangle). So obviously the guys clearing the land need to know the boundaries. Is there a type of survey where they will put markers every 100 ft. or so, and how do they do this if the land is heavily wooded? How much would this type of survey cost on that size property? Once it's cleared, obviously the fencing guys will be able to follow the markers for the fencing (since they'll be readily visible), but the boundaries need to be pretty precise for the land clearing first. Seems like this would be a nearly impossible task on 20 or so heavily wooded acres.

As far as land clearing, a friend recommended a very reasonably priced guy who did forestry mulching on his acreage. Anyone went the mulching route on their land? Any major cons to mulching as opposed to hauling/burning everything? I plan on leaving some of the bigger trees, but fairly sparse since my kid and grandkids will eventually be riding dirt bikes or whatever on the land occasionally. And the mulch, once tilled into the red mud, should make for much better riding dirt. Will keep a few acres wooded for sure though.