When touring in first-world countries, you can live without some form of position-determining system and rely only on maps (old-fashioned paper, or displayed on an electronic device) because road signage is continually present to tell you what road you are on, and where and when roads diverge. If all else fails, you can stop at a gas station or other public facility and reasonably expect to be able to get directions from another person who has experience driving in that area.

In lesser developed countries, road signage is not present or not well maintained, and a much smaller percentage of people you might ask for directions are drivers.

For those reasons, I would suggest you get a waterproof GPS navigator (meaning, a Garmin, or Tom-Tom, or whatever) suitable for motorcycle use rather than relying on your phone for position determination and off-line maps on your phone.

Most smartphones can determine position without needing a GSM (phone tower) signal, and there are many offline map packages that are just as detailed as what is offered on motorcycle navigation devices. But, phones generally are not waterproof, and the size of the text, control buttons, etc. on phones is a heck of a lot smaller than that on a vehicle navigation device that has been designed to be used while the vehicle is in motion. The vehicle navigation devices - especially those designed for use on motorcycles - are also a heck of a lot more robust than smartphones.

Considering the overall length of your planned trip, and the budget it will require, I think you would be setting yourself up for unnecessary headaches if you set out with only a smartphone for navigation... especially if your smartphone breaks (due to water exposure, an unexpected tipover, etc.) along the way.

My recommendation is that you use a purpose-built motorcycle navigator as your primary navigation aid, and use your smartphone with internal maps as your backup device.

With respect to your other question about 'how much cash to carry', my answer would be 'no more than you are prepared to lose or have stolen'. There are ATM machines almost everywhere these days, and you will always get a good rate of exchange if you withdraw cash from an ATM (except, of course, in countries with government-imposed artificial currency exchange rates). Take along an ATM card from your home bank (a debit card), and two different credit cards (for example, one Visa card, one MasterCard), and once every 5 days or so, withdraw enough cash from an ATM to keep you going in the country you happen to be in.

Michael