It does look daunting, but if you follow the instructions in the Wiki it really is fairly straight forward and there are many helpful individuals here on the forum to help if you get stuck.
I recall seeing a recent forum post that detailed a procedure where you didn't need to compile a custom PHP binary, but instead copied the existing binary and ini file from the DreamHost PHP install. (see link below).
I should note that the crontab steps detailed in that post are only required if you wish the PHP binary to stay updated as DreamHost update their install.
I have not used Moodle, so I can't really comment on the resources it needs to run efficiently.
Have you tried alternative CMS packages, to see if they run more efficiently here at DreamHost?
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