It is a super lens the 15mm Heliar, I use it a lot more than I thought I would. But I have no idea about the maximum decent ISO of the M240. With EVF you'd just have the lens which is both tiny and light.
I don't think any more gear is necessary!
Leica M2, Nikon D700, Bronica RF645, Leica CL, Summicron 40mm, Rolleicord Va, Hasselblad 500 CM Zeiss Planar, Leica 50mm Summicron V3, Hasselblad PME51 metered prism, Zeiss Ikon Super Ikonta 534/16 & Ensign 820 Special - all gone.