’ help me create a landing page for a client’ - No problem - ‘a page builder must include a configuration/layout similar to what they already have.’ is not a problem either.
Looking at your code - e.g. roadcourse.dominionraceway.com there is ‘a lot’ going on that might (stress might) make it ‘harder’ for your client as you state ‘They are not HTML savvy so that’s why a pagebuilder is a must’ but again not much of a problem as that can be ‘hidden’ away in code.
What ‘back end’ are you thinking of? php/mySQL or other. Personally I would hint towards using a simple framework such as bootstrap (or similar) as the base for the pagebuilder - I’m thinking ‘future’ now just in case they do become less non HTML savy and in the future might like to ‘play a bit’ themselves.
Would be happy to help out - could have a basic pagebuilder linked to a database based on ‘http://www.dominionraceway.com/’ very quickly. Would need a few hours to go through the site looking at the various options/layouts etc to draw up a base plan then not too long to create a ‘first draft’ for approval.
You can always email me via my profile here https://codecanyon.net/user/kwikbitzonline
Have a good day