Plumbing Access Holes in Wood Floor

I recently removed old linoleum tile and the underboard that had been installed below the linoleum in my bathroom. The floor below is decent variable width, pine, tongue and groove floor boards. I sanded these boards down and they look good. I have one issue that I need to resolve before finishing the job and coating the floors with polyurethane. There are two holes in this floor, one about three feet long be 1.5 feet that allows access to the pipes in the area below the floor (in front of the tub). The other is in the corner near the toilet and is about 1 foot square. These holes were originally made because this house is pre-indoor plumbing and access was needed to put in and service the pipes (I'm guessing). Both holes have existing removeable boards covering them that are flush with the floor, but they are not fit exactly in the opening and they move a bit when walked upon.
I want to still be able to access these openings to get at the pipes, but I want these holes to be fit nicely with boards that are exactly flush, and are solid when walked upon, and that look decent. What is a good way to do this? Should I use a hinge, or have the wood just drop in place? Also, what is a good way to give support from below? Currently it looks like a two by four was screwed underneath on each side of the holes creating a "lip" that the boards to sit on. I'm a bit perplexed at fixing this and am considering getting a carpenter instead.
Any ideas?
Rob PA
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Ye gads hidey holes, God help you if you ever have a police search. My suggestion is get a carpenter to look at the situation.
PS I know they are out to get me...
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Depends on what you mean by "look decent". Was it me, I'd use countersunk wood screws to hold the board (planed to fit) in place, and fill the holes with wood-putty. Then when you want the boards out, you dig out the wood putty, and unscrew the boards. The problem, if you use that technique, is that the screw-holes will always be visible. If you want something that's undetectable from above, then the problem gets harder.
--Goedjn
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.