For longer distance cycling adventures, steel is still the frame material of choice. A good steel frame provides a much more comfortable ride on bumpy roads than aluminium — and unlike aluminium or carbon fibre — can be repaired by a competent welder. We don’t ride with suspension forks (to avoid failure in remote places and expensive maintenance) but for shorter tours on rough roads they can be great. Flat handlebars, comfortable grips and a saddle you're accustomed to will keep you happy on the bike.
29-inch wheels are the most popular size for long-distance touring, but 27.5 inch is the wheel size of choice for domestic bikepacking adventures or tours of up to a few months. Bear in mind that in developing countries tyres and other parts can be scarce; it’s essential to have some bike maintenance knowledge and to carry some spare parts, such as cables. Running your inner tyres with sealant reduces punctures and ensures your bike handles well on a variety of terrain. Don't skimp on your tyres, as nothing will sap your energy and enthusiasm like regular punctures.
Mechanical disc brakes are superior to rim brakes; you can still ride on a buckled wheel, won't destroy your rims over time, and they work better in wet conditions. It’s near impossible to insure a bike on a long overseas tour, so don’t go overboard with titanium and top-end components. Keep it practical and durable. We generally aim for Shimano SLX or XT components for their replacement availability, and the only titanium parts on our bikes are the handlebars — for absorbing the road bumps.
This will all depend on how and where you choose to go bikepacking: research a setup that suits the style of riding you want to do.