Sounds like a fun project.  Making a reasonable valve shouldn't be tricky - but...  steam is a lot like wind, there is a lot to it, a lot of research has been done and to be even reasonably efficient I think a lot of research is involved.  Last time I ran mine I carefully weighed the coal and monitored KWH output and came up finding that I was running between 2-4% (depending on the quality of the coal which I am not sure) efficient.  (probably I was running about 3%)  Of course, when I fired it all up all the equipment was at -4 deg F!  I expect better efficiency in the summer.

'Any links would help. I've looked until I'm fed up but I'm still looking.
Yep switching from wind to steam.'

Steam is great fun and workable, but to get a steam system thats not very labor intensive will involve a lot of work/money.  Wind is free - once you get it setup there's very little cost/labor involved to keep it running.  If I was to say such a rediculous thing (sorry) that 'Im switching from wind to steam' and actually kept my house/shop powered up I would have a full time job cutting wood and playing 'engineer'.  You don't walk away from a steam system, it requires constant attention.  Lots better than peddling for power but compared to a diesel engine running on vegi oil (if you're worried about renewable energy) or an internal combustion engine running off a gasifiers - steam is a hell of a lot of work, takes a lot of fuel and a lot of water.  

My current "vapor-ware" make-up water feed pump (MUWFP?) is a pressure washer pump that runs constantly, and water is either added to the boiler-tubes or bypassed by operating a 3-way valve (through a check valve, of course). The crankshaft runs the PMA and also the MUWFP.

The simplest way to start out is a total-loss system, where cold water is added and converted to steam, and then the exhaust is vented to the air. (side note: if the hot exhaust is piped to the top of an elevated aluminum radiator that is above a roof-cistern, most of it will condense into distilled hot water with a gravity feed to the cabin)

If a large insulated tank (salvaged 500 gal propane?) is kept as a reservoir, once it is warmed by the condensing exhaust, you will be feeding the boiler 200F water instead of 50 F water.

The 400 gallons of hot water can also be used as a DHW pre-heater, or for a radiant floor heating system.

The plan will probably change (if I ever actually do something) but I'd like to try 10 ft of 1/2" (dash-eight, meaning 8/16ths) stainless steel hydraulic tubing filled with sand to prevent kinking and wrapped around a pipe to form a coil. The constant duty pressure rating is 3,000 PSI and burst is 4,500 PSI.

I figure the Franklin stove and boiler tube (also the feed control valve) will be inside the shop, and the relief valve and the rest will be outside surrounded by a solid  wall and an open top.