building a deck walkway

hey peeps all new to this so bare with me.
Ive just fished buildin a 3x6m patio deck using the ledger technique. I got most of my ideas and info from reading the posts on this site. VERY helpfull guys. The deck turned out trumps and solid as, lets just say there was a few beers consumed admireing my handy work. Jarrah is such a beautifull timber.
Now im onto the next job a 7m x 1.5m deck walkway from the front door to the drive way. from the house it will extend 1.5m then kick out to about a 115-125 degree to the major part of the walk way leadin all the way to the drive. one of the problems is the low profile of the walkway. I have a few questions 1; can I get away with a singular bearing frame as aposed to bearers and joists, would it be ok to build a frame with the nailing points for the decking within the 450mm range.2; What is a good span for my styrups at a 1.5m width and 3; I'll be useing structural treated pine should i paint the TP as the bearing frame will be surrounded by mulch and gardens, if so what product should i use. Any help would be appreciated
Thank SAMBO:U