Offline topographic maps for remote areas

I guess OsmAnd could fit the bill if nothing else is available, but I find their topo presentation a little lacking.

I will be traveling to the Himalaya next spring and would like a decent way to look at and locate myself on an off line topographic map on my iPhone.

If Internet is available, the maps from either OpenTopoMap or CalTopo,-118.28585&z=14&b=mbt are nice. But I won’t have Internet connectivity.

On CalTopo I can create custom geo-referenced PDF map files using OSM data which I can use off line in apps like Avenza. I have used this to good success for trips in the United States. But for Nepal (and maybe anywhere outside the United States) CalTopo does not have the elevation data (contour lines).

If I could create geo-referenced TIFF or PDF files with OpenTopoMap it would be great but I don’t see any way to do that.

Are there some alternatives for off line OSM based topographic maps with decent rendering that I am unaware of? Or must I live with OsmAnd for this?

I was going to say, Locus Map Pro, until I saw your mention of iPhone. Do you have an Android by any chance? (Rugged Androids can be had cheaper than low-res Garmin handhelds.)

Locus works brilliantly offline, with topo contours, slope shading, and on-the-fly theme switching to adjust the look. But Android only.