Although in Portugal since the beginning of last week, Cooper has continued to speak with players and agents in his bid to bolster Quakers' squad.
He hopes to soon make more additions having last week recruited striker James Walshaw and midfielder Kris Taylor.
Darlington have been linked with several players and Cooper admits he is awaiting a response from a number of targets, but some have proved reluctant to put pen to paper.
He said: "We've made offers to a few but nothing concrete has happened yet. There's a few hedging their bets.
"We've got lots of targets in mind, but a lot of players don't want to commit at the moment in case someone like Luton or a Football League club comes in for them.
"It's a bit cat and mouse. We're telling them that they are better off getting fixed up now and taking our offer because if they wait four weeks we might end up bringing someone else in, so our deal then may no longer be there. Or, if it is, we might not be offering the same money. It's a catch 22 for both parties.
"I'd know that if I was playing I'd want to be sorted before I went on holiday, so I could go away knowing that I'd be coming back to the security of a contract."
Meanwhile, Darlington have asked supporters to help maintain The Northern Echo Arena during the summer.
The club plan a number of spring cleaning and painting jobs over the next few weeks to give the stadium a mini-makeover.
General manager Alan Murray said: "There are lots of odd-jobs that need doing and we're keen to get as much help from fans as possible.
"There's a lot of cleaning and tidying up to be done, both in the seating areas of the stadium but also inside the concourses and hospitality areas. We'd welcome any help from fans who'd be willing to give up a bit of time to help us save money during the summer."
n Fans who are willing to help should call the club on 01325-387000 and ask for Steve Holmes.