Get started on wikipedia and gain some experience doing small edits and learning the ropes. Time enough for big ambitious edits later.
I guess I might still try to rewrite the Obsidian Chronicles articles, but that still might be too ambitious for me, because in their current state, they are going to need alot of work, and im not all that fluent on the wiki programming language and formatting syntax etc. etc.
AutoWikiBrowser is a specialized external semi-automatic editor designed for editing Wikipedia pages fast. Its main purpose is for doing search/replace operations on many pages. It can also append or prepend material, and you can do regular editing with it as well.
First you make a list, using AWB's listmaker, of the pages you wish to work on. Then you specify the search/replaces you want done. Then you click Start. AWB loads the first page on the list and shows you the changes it made, if any. If the changes are acceptable, you click Save, and AWB saves the page on Wikipedia. Then it automatically loads the next page on the list. AWB can even run scripts, and perform regex (regular expression) search and replacements.
In order to use AWB, you must either be a sysop or an editor with over 500 edits in the main namespace.
For on-the-fly general discussion and support requests for AWB, try the AWB IRC channel: #AutoWikiBrowserconnect