To my knowledge nobody makes a photo-etched detail set specifically for this kit or this scale - and it seems unlikely that anybody will. Gold Medal Models does make a few sets that might help. One consists of 2- and 3-bar railings on 1/200 scale. They'd be a little big, but close. Then there's a set specifically designed for the old Revell Coast Guard vessels Campbell and Eastwind. They're on slightly smaller scales, but the ladders and some other parts might work. An easy way to get to Gold Medal Models is via the Steel Navy website, <www.steelnavy.com>. Just click on the Gold Medal icon.
The Revell Eagle is a grand old kit - a "classic" in every sense. I wish they'd reissue it, if only for purposes of nostalgia. In terms of producing an accurate scale model it does have a couple of problems. You may want to stop reading here.
In the first place it attempts to represent the ship as she looked when the model was first released, in the mid-fifties. Since then the Eagle has undergone many, many modifications. The two saluting guns on the forecastle deck are gone, the boat complement is completely different, there are all sorts of new antennas on the masts, there's a big pilothouse on the quarterdeck, the mizzen mast has a double spanker rig, and (perhaps most conspicuously) the bow is adorned with the notorious vermilion-and-blue "Coast Guard Slash."
More seriously in terms of scale accuracy, I'm pretty sure the hull proportions are off. I think (though I'm not a hundred percent certain) the kit is based on the plans by Harold Underhill, which were published in his book Sail Training and Cadet Ships shortly before the kit came out. Underhill was a fine draftsman and researcher, and the drawings are excellent. The problem is that the Eagle was one of a class of ships built in Germany during the thirties, all of them quite similar but not identical. Underhill based his drawings on the plans of the Gorch Fock (later the Soviet training ship Tovaritzch), which was similar to the Eagle in most respects but, if I remember correctly, about twenty feet shorter. Underhill was absolutely up front about this in the text of his book; he wasn't trying to deceive anybody. Unfortunately the plans he drew have been marketed over the years as representing the Eagle, without explanation. Most Eagle kits (including, I'm fairly certain, the Revell one) are based on those plans, and thus represent the Gorch Fock's hull.
Some years ago I got commissioned by the Coast Guard Historian's Office to make an up-to-date line drawing of the Eagle, and this problem was explained to me. (The Coast Guard isn't trying to deceive anybody either.) The CG Historian, Bob Browning, and I did, on rooting through the files in his office, find a couple of sheets of old blueprints clearly labeled "Horst Wessel" (the Eagle's original name) that I used to establish the right hull proportions. At various points in the ship's career Coast Guard draftsmen have done several other drawings of her, based on freshly-obtained measurements. On the modeling front, scratchbuilders should have no trouble finding accurate drawings of the Eagle.
Changing the proportions of the grand old Revell kit would be quite a project. (On that scale we're talking about a difference in length of an inch or thereabouts.) I can't blame anybody who thinks it wouldn't be worth the trouble. As I said earlier, I tend to think of that kit primarily in terms of its nostalgia value. The original boxtop artwork alone is enough to knock your socks off.
Hope this is of a little interest - and not too discouraging.