The original KJV 1611 has "The Epistle of Paul the Apostle to the Hebrews"
That verse gives the "appearance" that the writer received his epistle "second-hand" (as you suggest). But the actual wording of that verse says no such thing. So let us look at that verse carefully:
OUR SALVATION IS A GREAT SALVATION THUS A WARNING THAT IT SHOULD NOT BE NEGLECTED
How shall we escape, if we neglect so great salvation;
THE GOSPEL OF SALVATION ORIGINATED WITH THE LORD
which at the first began to be spoken by the Lord,
THAT GOSPEL WAS CONFIRMED TO THE WRITER BY CHRIST'S APOSTLES WHO HEARD HIM PERSONALLY
and was confirmed unto us by them that heard him;
Nowhere in all this is there even a hint that the writer did NOT receive His epistle by Divine revelation. Just goes to show that if we do not examine the words carefully we can be jumping to false conclusions. What Paul is saying is that the Gospel which he was taught directly by the Lord was confirmed to him by the apostles, who extended to him the right hand of fellowship. But Paul received all of his teachings by Divine revelation, and directly from Christ (see Galatians 1).
Furthermore, Paul is clearly shown to be the spiritual father and mentor of Timothy, and he refers to Timothy in Hebrews as follows:
Know ye that our brother Timothy is set at liberty; with whom, if he come shortly, I will see you. (Heb 13:23). The close connection between the two is obvious in this verse.