Convert everything to RAM. It's lightweight and appreciating in value every month!

Plain old money would work fine, if you want something easily transportable. Simply sell the asset, then go to a currency exchange and exchange it for the currency of where you're going. Or, in some cases, you'll be able to just keep it in US dollars, because in some countries US dollars are widely accepted alongside the local currency.

Obviously, you can't bring real estate assets with you -- those would have to be sold and then you transfer the money to your new overseas accounts. For any cars you own, it's probably best to do the same, as the cost of transporting them could be high. But if you're really attached to a certain car, you could definitely have it shipped to your new home if you want to and if it fits within your moving budget. For any other valuable tangible assets you have (anything small enough to easily transport), you could also just take it with you. Of course, the most likely case is that most of your assets are intangible -- bank accounts and the like. And that's easy enough to transfer into your new overseas bank.

Anyway, if you're drowning in student debt and struggling to pay it off, you probably don't have very many major assets to worry about in the first place. I'm guessing that most people in that situation don't own a house or have any big investment accounts or stockpiles of gold or anything. It's likely that they don't even own their car outright, or if they do, the car is worth so little money that it's barely worth worrying about.

I don't think it would take more than 2 or 3 kg of gold to pay off a loan. But I'm not American, so