IMO, footed posts, and brackets are far easier than dealing with lumber, and the effort saved is well worth it. Just build your bridge panels the size you want them, then drop them on the brackets. Also, consider that floating bridges probably require moving/sliding sections on the banks as the water level rises and falls.
esshup and I have built 3 docks, and all three were with Tommy Docks hardware. Look specifically at the muck feet and galvanized posts. Also, unless something has recently changed, if bought through the big orange box store there's no shipping costs. If you're doing this manually, and won't move deck panels with a tractor, then deck the pressure treated frame once it's in position on the brackets.
TD hardware
