I'm planning a short course on few topics and applications of nonlinear functional analysis, and I'd like a reference for a quick and possibly self-contained construction of a structure of a Banach differentiable manifold for the space of continuous mappings $C^0(K,M)$, where $K$ is a compact topological space (even metric if it helps) and $M$ is a (finite dimensional) differentiable manifold.

A construction of a differentiable structure of Banach manifold for this space can be found e.g. in Lang's book *Fundamentals of differential geometry* (1999). The main tools are the exponential map and tubular nbds  (having fixed a Riemannian structure on $M$. This is OK but I believe there should be something even more basic. 

Does anybody have a reference for alternative constructions (not necessarily elementary) ?