Website completion of back end and some addition pages

Hi we have had 2 attempts at completing our site and both times the results had incomplete backends that were not finished. we are wanting the site to be completed as a whole to be used by website dummies or staff to be able to manage. this is for a rental motorcycle site for rentals + tours which needs the ability to add or remove multiple bikes or tours to the booking form to be sent to you for final approval and quotes part 2 will be the completion of the Tour pages / a basic 1st page with all tours shown basics of the tour in a compact way when selected will open into a full tour info pack of that tour part 3 Motorcycles for sale needs to be updated to a much better format and style for selling motorcycles basic information pages showing all bikes for sale opening into full details with enquiry feature most of what we have is in place already full details will be supplied during chat or request with a word doc website must be PHP based or Magento Mobile ready as well i think a lot of the feature we need is self explanatory for a rental site