GURNEY (AYGN) to HENDERSON (AGGH) is 580 nm, GURNEY to BUKA (AYBK) is 390 nm, and HENDERSON to BUKA is 400nm. Would have thought that if tracking DCT GURNEY HENDERSON on route B598 that the closest point to an airfield (BUKA - for the Fokker at least) would be at the halfway point, and then it would still be outside of 200 nm, - about 250 nm or so.
AGGM is also suitable - Solair operate an A320 in there every week, so it will take the Pixie 73's and F100's.
However, it is still a bit out of the 200nm, so reverting back to 200nm from land, it can easily be done, using POM, GUR, MIS, MUA, HIR. Plenty of other islands along the route, but that one covers it.
Great Circle Mapper