I read you about jumping in. I think bigger systems are probably more forgiving but there is more cost at risk if something does go wrong, so you need to know what you are doing to effectively manage it. I think if you can build and run a small set up, it is possibly a steeper more intense learning curve but that prepares you for bigger and better things in the future.
If you built outside, you could position the system close and handy to your house and maybe build a small greenhouse and put your system in that. Or if you do it indoors you already have that, but an indoors system may require lighting? so that will add another complexity to get tour head around. It is still achievable though. Both ways have their pros and cons. The duck coop sounds good too. Plenty of ideas to make a decision, let's know what you decide and how you get on.