assigning directories/domains for wordpress blogs

sorry if i'm repeating a post elsewhere...

i'll try to explain this questions simply; i have 2 domain names, one is already hosted at dreamhost, second will be shortly, i'll call them mydomain1 and mydomain2.
i'm installing wordpress for 2 blogs, one for each domain.
mydomain1 has been at dh for ages and i have all sorts of random stuff in directories which i'd like to keep. currently mydomain1.com is mapped to an html page.

first, i would like mydomain1.com to be mapped to the main page of its wordpress blog (so when you go to mydomain1.com it goes to the blog of the same name) and be able to have any subdirectories, cats etc for that blog be under it. i also want to keep my old random junk under the same domain somewhere. what's the best way to do this?

should i make a directory called mydomain1.com/blog and install the wordpress stuff there? that way all the other old/random stuff (mydomain1.com/mov, etc.) would remain as is.
if i do that, will it be basically a redirect so that what will appear in the window will be mydomain1.com/blog/subdir,etc.? Is there any problem with this? also (not necessary vital, just curious) is there a way to make the "blog" dir "invisible"?

or is there a better way to do this? is there any reason it's better to install the wordpress blog dir at the root?

then should i do the same for the mydomain2.com blog (dir called mydomain2.com/blog) for consistency's sake? there won't be any existing subdirectories as i will just be moving the 2nd domain over to dh, so again, is there any reason i'd actually want the blog stuff installed at the root?

thanks for any assistance!

Rename the current mydomain1.com to mydomain1.old. Then create an empty mydomain1.com folder and install WordPress there. Then you can move the old stuff back, one item at a time (as long as there are no name conflicts). WordPress updates won't kill unrelated items in its directory.

Both blogs should be installed at root if they are your main site for their respective domains. Don't install them at /blog, as that just makes a mess of things.

-Scott

thank you! i believe that is exactly the answer i was looking for.