Another thing that might help has to do with that FE/BE split and what is open.
First, I NEVER EVER directly open a table in the backend. I open a query in the frontend and the query refers to the table. This allows me to set the query for optimisic locking, so the tables NEVER lock until I'm about to do something with them.
Second, I have one query that never dies from beginning to end of a session. This query is ALSO optimistic-locked, but it stays open. When the other queries open up their corresponding backend tables, the fact that an internal link is open with the same file specification somehow helps Access find the other tables faster. I.e. it "rides" the open connection rather than opening/closing connections all over the place.