Roof Covers are not difficult to install... no matter what the model if RV you own.
BUT... if your considering installing one on the Fantastic Fan vent... you will discover a problem... the company that makes the fan recommends not to use a Cover.
This is off their Q & A ... part of their Site.
<TABLE border=0 cellSpacing=4 cellPadding=4 width=612><TBODY><TR><TD>
[FONT=Arial, Helvetica, sans-serif]Q.[/FONT]
</TD><TD colSpan=2>[FONT=Arial, Helvetica, sans-serif]
DO YOU RECOMMEND VENT COVERS?[/FONT]</TD></TR><TR><TD vAlign=top>
[FONT=Arial, Helvetica, sans-serif]A.[/FONT]
</TD><TD colSpan=2>[FONT=Arial, Helvetica, sans-serif]
Vent covers restrict the airflow of your Fan-Tastic Vent by about sixty percent. In addition, covering your vent requires more frequent cleaning due to dust and dirt accumulation. Although we do not recommend any cover over your Fan-Tastic Vent, it will not void your warranty.[/FONT]
But if your going to install a cover over a vent other than one of those... you should be able to do the install with just a few hand tools and a cordless drill. Working from the top of the RV... holes are drilled into the Vent Frame... attaching brackets that come with the vent cover... is all that's left. They are not built to be tight to the Rubber roof... but are held above the surface by the brackets.
Good Luck !
</TD></TR></TBODY></TABLE>