Photoshop :: How To Best Open 35 Mm Slide RAW Scan With 4000 Dpi In Camera RAW CS5

I have, at present, set Camera Raw to open files as ProPhoto RGB and as 360 dpi. I want to keep all options open for later use of the files (for albums or enlargements). How do I get the best results so that I do not diminish the quality obtained in the scanning process (where I try to use only ICE and to leave all other editing to PS later - I know that the changes made by ICE are permanent so that I already here do not have a real RAW - but it is my impression that the choice of RAW over TIFF in the scanning is still worth it).
 
I have also some older scans but these are TIFF's, also 4000 dpi but only 8 bit. I want to get the best result from both types of files.
 
I plan to perform all edits before I finally save files in various print sizes. I am still quite scared as to make mistakes when resizing so that I get an inferior quality in the new size.  I, of course, keep a copy of the original scans safe and unedited. I am also in doubt as to whether I should go directly into PS or via Camera Raw with the scans.