Embed a node add form on a parent node
Inline EntityForm is for placing an entity's form within an Edit page of an existing  Node, eg (/node/edit/123). It's not for showing a form on a Nodes' page with a view_mode set to like full.

You want to use either:


webform entity
entityform


And then either use Display Suite or alter the Node Template for your theme to include form for reservations when people view your Node.

Alternatively you can just use 2 content types: 1 for product and 1 for reservations. and use the Prepopulate module to build a link to create a Reservation -- which you can place on the product node. Clicking this link would send the user to create a reservation, you could always send them back to the product node using $form['#redirect'] on your reservation type.

And if you were crazy you could try to make a url using Prepopulate that loads an Ajax popup node reservation form on the product page.

Hopefully one of these ideas sets you on your path.