I'd buy 20 BTC worth of $ETH lock it up and check back in the year 2018...
Settle my loans with the remaining 20 BTC
Thats assuming that if the ETH value remains to catch up with btc values and volume.
You wont know what happens with alt coin on a even month to month basis so I wouldnt take my chances to leaving it to 2 years.
Unless you are aware of the news that the smart contracts are being used are common, then thats a different story.