He is also expected to challenge the "disastrous amnesty and border policies" of his successor, President Joe Biden, the source added.
Mr Trump, who was impeached for an unprecedented second time for his role in fomenting the 6 January assault on the US Capitol, nevertheless remains a potent force in US politics.
Three-quarters of Republicans want Mr Trump to play a prominent role in the party, according to a poll from Quinnipiac University this week.
Since reluctantly departing the White House on 20 January and ceding to Mr Biden - despite his constant but unsubstantiated claims that the election had been stolen - Mr Trump has largely kept to himself at his Mar-a-Lago estate in Florida.
Stripped of his Twitter megaphone, he called into friendly cable TV news programs this week after the death of conservative radio host Rush Limbaugh, musing on far-right channel Newsmax about the possibility of a future political run.
"I won't say yet but we have tremendous support. And I'm looking at poll numbers that are through the roof."
"Let's say somebody gets impeached, typically your numbers would go down, they would go down like a dead balloon. But the numbers are very good, they're very high," he said.
And in perhaps a preview of what might come at CPAC, Mr Trump issued a statement Tuesday ripping into top Republican Senator Mitch McConnell, who had delivered a scathing rebuke of the former president despite voting to acquit him of inciting an insurrection.
"The Republican Party can never again be respected or strong with political 'leaders' like Sen. Mitch McConnell at its helm," Mr Trump said in the statement.
"Mitch is a dour, sullen, and unsmiling political hack, and if Republican Senators are going to stay with him, they will not win again."
A number of top Republicans who are considered possible candidates for the party's 2024 presidential nomination are also due to speak at CPAC, including Mr Trump's secretary of state, Mike Pompeo, and Kristi Noem, the governor of South Dakota.
Mr Biden, who is trying to steer the United States through the COVID-19 pandemic and an economic crisis, has tried to avoid discussing Mr Trump, at one point calling him "the former guy."
Lawmakers from his Democratic Party have unveiled legislation to create a path to citizenship for 11 million undocumented immigrants, reversing Mr Trump's hardline policies.
Small numbers of asylum seekers, most of them Central Americans forced to wait in Mexico under Mr Trump, have also begun crossing into the United States as their cases are being processed.
With reporting by Reuters.