TikiWiki can run in PHP SafeMode, which is common in shared hosting environments. If your host allows you can certainly use the rewrite rules in a local .htaccess file. Dont worry too much about accelerators at the moment, but again if you want them, they need to be setup by your host.
For starters you will be fine running it in Safemode, I did for 2 months with www.damosoft.co.uk, but now I have my own Web Server up and running
Hope it helps, if you want more info, please get in touch with me.