Website setup question

[OneGrassRoot]

I want to create a resource directory as part of a website. For different reasons, I'm thinking of installing it separately.

I always have this idea that if, heaven forbid, a website goes down for some reason, if another part of it is up because it's not part of the same FTP installation and/or URL (sorry, not sure of correct terminology), that's a good thing.

I'm not sure I need the resource directory to be part of the database for the main site, so is there any reason why having them separate -- simply linking to one another as seamlessly as possible -- is a bad idea? I suppose the obvious answer there is that I'm talking about separate hosting accounts -- and thus more expense -- huh?

Plus, I don't want to have to rely on the current webmaster to install this; it could take forever. If I set it up separately, the company where I'm getting the resource directory program would install. I could be up and running much easier this way.