I am not certain I would mess with it. Like @James89 mentions, it is not worth moving a stud for anything less than a king’s ransom. Gurley is not really that old. He has solid value in Dynasty.
That said, the offer is not bad but I would absolutely hold out for the 1st round pick. I know it is a dart throw, but it is solid trade bait in dynasty especially. But this is not a trade I would just automatically make.
Getting all those pieces likely tips the scales ever so slightly in your favor. I can see a strength in WR and a dip, but not a drop, at RB as enticing. Your WR need more secure players IMHO. Lots of potential there but not (yet?) security. Same with RB, but you have a stable of nice young studs with upside. You would definitely come out of this with two set-it-and-forget-it players which helps with your FLEX situation.
This trade is certainly not the king’s ransom you would hope, but it is also not an insult. I can see taking it if you like to play a bit more risky. Stay put if you would rather keep a little conservative. No problem with either, just style choices.
If you do take it, I think the 2019 1 should be asked for with Kerryon since he is also unproven in a muddy backfield. Consider it hedging the risk that Hunt splits more with Ware being back and Kerryon does not quite pan out.
I hope something in this rant helps