I don't know what info or dates you seek - if IoM census then you can buy CD roms of any IoM census for about £15 each, their quality is actually better than those on microfilm at manx museum, the 1881 is both free on line and I think still available on a CD ROM set for a very reasonable price, the 1901 is effectively pay/view with a free index.
Brian's index to burials will give you an excellent guide to those needing further check at the Manx museum (you could always buy copies of burials/MI's etc for a few pounds if it is one parish that dominates).
The IGI for all I criticise it, will give a good indication of which parish regs need looking at (and as far as I know these are not available other than on mormon microfilm or at Museum/general registry).
The will index by Brian will again pinpoint those needing further study - transcriptions or summaries of many (my guess about 7.5% - 10%) are available on either Brian's site or Manxnotebook.
Property records again are only available at Manx Museum/Gen Reg or on microfilm (tho some transcriptions are available on manxnotebook + possibly elsewhere).
As it would seem you are based on the Island a focussed afternoon in Manx museum (eg Sat) could suely provide you with enough data for a week of further investigations.