"So are you saying all of our carrying costs, including property taxes, can be deducted as investment costs but only through 2017?"
No. Up through 2017, carrying costs could have been deducted as miscellaneous itemized deductions subject to the 2% rule. They would have been deducted on each year's tax return, assuming that you itemized your deductions and that you had enough miscellaneous deductions to make a difference. It is too late now to amend those prior tax returns to claim the deduction, and you can't deduct prior costs in the current year -- partly because that's not how taxes work, and partly because the miscellaneous itemized deduction has been eliminated. In lieu of taking the expenses as miscellaneous itemized deductions, you could have capitalized them. But if you did not, it is too late to recover them now.
Advertising is an allowable selling expense that reduces your selling price when figuring the capital gains. Advertising expenses are not allowed to make changes to the property. For example, when selling a house, you can deduct "staging" as long as you make no changes to the house, but if the real estate agent also recommends painting, that is a maintenance item, which is not allowed as an adjustment. (There are never adjustments for maintenance, because maintenance is the routine and ordinary duty of every property owner.)
Whether staking is an advertising expense, I leave to your risk to claim or not claim. It changes the property (like painting), but the stakes can be removed (like taking the rented furniture back after staging).
Brush hogging sounds like routine property maintenance that is your responsibility whether or not you sell the property, so it sounds like a cost that is not an improvement and not advertising.
You simply report the cost basis, adjustments, and selling price on your return. Keep records for at least 3 years in case of audit (6 years is better).
