OK, to clear up a couple of things here. QRSS is ultra slow morse code. Not at all what you're looking for I think. Yes, it can travel really long distances on low power, but you aren't going to download Netflix videos with it unless you have amazing patience and a 10 thousand year lifespan. :D
QRP and QRPP are low power signaling in the ham radio service, and can incorporate many modes and speeds. Looking at QRP information will give you a feeling for how much you can do with very little power, but long distance communication on milliwatts normally takes place in the HF range, not microwaves where broadband networking operates. Yes, you can go a long distance with just line of sight as long as conditions are good at 900MHz. However, beware of the FCC regulations. There are restrictions on what you can do with those type accepted routers and switches, and what kind of antennas you can use without special permits or licensing. I don't know all the ins and outs, but the hams using broadband Mesh networking get away with some tricks because they are in a shared ham band and have licenses. Be aware too that setting up high gain directional point to point antennas requires a lot of patience to get them aimed right and some skill at installing them so the wind won't change the aim on you. Good luck, and let us know how you get on with it.
