First you should use the ratio land to property value you used when you put the asset in service even if you don't like it ... the profits on the land and bldg are both taxed the same way in the end so don't let the figures startle you.
Preferred method is to simply sell each and every asset in the program ... complete an excel worksheet to get the figures you need ... the program only needs 3 ... date of sale, % of sales price & % of cost of sale. The land should have been listed as a part of the original property cost and will be handled the same when you sell it.
The other option would be to take each and every asset out of service in the Sch E asset section. Then print a copy of the depreciation worksheet and use that to combine all of the like code assets together and enter it later in the interview under sales of business assets.
Neither option is fast but they are both doable ... your choice as to which one you use.
