The best place to build in Sanctuary is over by the actual river by the playground equipment. I just use Concrete or Stilt foundations its a snap.
->WHY cause there are no spawns over by the Playground and Sanctuary has enough Water Space to build like 10 Water Purifiers...
The problem I run into constantly is that even if I scrap all the available wood at settlements its not enough. I scrap everything, pick up everything, and buy up those measly 50 wood shipments...Still not enough.
50 wood shipment is soo little amount, they need to offer me amounts of around 10,000 Wood per shipment otherwise its just an aweful waste of time.
Here is why, most wood structure parts is about 10 Pieces Per. Of course you get some parts for as little as 4 Pieces but if you stop to think about it your going to assemble something like 300-500 Parts...For one building.
Walling off the settlement geez that just seems like a waste of good Resources that I could have used to build some really cool structures that you know also have their own walls 
I have more than enough of all other Resources but Wood...Wood is way more needed for building actual settlement buildings and what with what 30 settlements and not all of them coming with buildings already standing and waiting for you well guess what you need loads of this Matt.
Screws HA, not rare at all, Adhesives?? Have you seen my glue factory?
Aluminum not rare at all, all the high end resource stuff man that stuff isn't nearly needed as much as Wood Resource.
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Have you guys even considered building a structure over the Water to house your NPC's?
Makes for a very nice funnel.
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Scrapping Stations, sure these are nice, but they cant keep up with my pace of building.
"Why cant you all be like Settler #12! Number 12 hit pay dirt the other day discovering a hidden cache of Broom Stick Handles at the local Janitorial Store."