For the tank, brackets or a base that attaches to the tank can be done with no welding.
I can tell from your plumbing choices, linked above, that you're inexperienced with propane systems. I'd suggest to hire this out or get experienced help. Pressurized gas carried on the road is nothing to mess with. One mistake and it will be a mess.
If you want to tackle it, use black iron pipe and tee off to soft copper, thence to appliances. As was stated, it's been done this way for years and meets safety requirements.