Coding bounding boxes

Idea 1

Code 2x1, 1x2 and 2x2 houses with huge BBs, that cover several tiles. Draw them for every tile
Pro: single sprite
Contra: more dark in transparent mode

Idea 2

Code trees and object in separate BBs
Pro: Trees would fit the trees set

Sample code

// SW
 1423 * 17     02 07 01 00 00 00 00 80 04 80 00 80 F0 00 20 10 40
 1424 * 25     02 07 02 02
                 02 00 00 80
                 04 80 00 80 F0 00 00 20 10 40
                 05 00 00 80 00 00 80
 1425 * 20     02 07 03 81
                 62 00 2A 0F \2|
                 62 0F 0A 0F
                 01 02 00 04 04 01 00
// NE
 1426 * 17     02 07 11 00 01 00 00 80 04 00 00 80 00 00 20 10 40
 1427 * 25     02 07 12 02
                 03 00 00 80
                 04 00 00 80 00 00 00 20 10 40
                 05 00 00 80 00 00 80
 1428 * 20     02 07 02 81
                 62 00 2A 0F \2|
                 62 01 0A 0F
                 01 12 00 04 04 11 00