Ah, well you won't be doing much with big files if you haven't got your machine expanded. Not being able to run IBrowse means your machine is pretty limited, and working with large images and audio files is probably going to be tricky too.
Documents are the single biggest issue for me too. I wrote my thesis on my Amiga back in the day (2003!), exported it as RTF and did the final formatting in Word. It worked for the text, but all the images had to be re-inserted.
As for controlling stuff however, I've used Amigas in a Raspberry Pi sort of capacity in the past - running small LCD modules and using custom hardware to automate things. Sure, you could use an Arduino and it would be cheaper and smaller, but where's the fun in that