Google documents is great, as suggested. It's good for if you need to keep your files private too. Everything is saved online on your personal account not on the computer. I think you can access it through a phone, but I'm not sure.
As for an altar, blogging sites are commonly used for e-shrines. You could make a tumblr blog for the deity or spirit to which you wish to build a space for by only reblogging content you feel the entity would enjoy.
For a magical altar, I have no clue as this would be a place where things are performed. I haven't given it much thought, but I'm sure you could think of something creative! Perhaps making a photo aesthetic of things you feel suit the purpose?