Edit: Put in a Consolidation effort based on comments and side research
Jewelery is good getting through customs as some countries have limits on what you can take over borders. Canada for example has 10k limit before you have to delcare and it is not clear if per person.
1.a) Always buy jewelry you plan to wear anyway because you will not get full value back.
1.b) Buy from reputable locations. Looks like Mene was a popular one.
Gold coins are good but get normal ones like Eagles, Buffalo, or Maple as it's easier to sell. Fancy ones are cool as collector item but will require more haggling.
2a) Bars are cheaper over spot but can be harder to sell overall
2b) Seems like libertycoin had consistent reviews.
Cash is light but if your origin country currency dips then it's worthless.
Crypto requires you to have your wallet seed and importantly access to a pc and electricity.
Make sure to have a backup skil/trade to live off of.
Transferring money between banks can have legal issues.
Besides the utility of a go bag.. having portable wealth can get you into trouble with the police or border crossing agents.
Civil asset forfeiture is a very real thing at border crossings. If you must take portable wealth have documentation about where it came from a available
US police (including border agents) are stealing things from citizens. It doesn't matter if you have bank statements or receipts if you are dealing with someone who will just steal your shit and claim legal immunity.