Although safety is a primary concern in choosing your initial base location, there is a secondary consideration you must take into account as well.  This modpack contains GregTech, so this is the major source of ore generation.  Although there are small pockets of the Thermal Foundation metal ores scattered equally through out the entire world, you are going to need to find ore veins for the majority of your metal needs.  Specifcially, GregTech progression begins with the "Bronze Age", steam powered machines that are constructed out of bronze.  Bronze is a mix of three copper and one tin.  Both copper and tin veins spawn at higher elevations so you will want to have access to a mountainous biome with exposed stone so you can see the veins poking out on the surface.

For copper, you are looking for a mineral called tetrahedrite, it spawns between Y80 to Y120.  There is another option for copper though, chalcopyrite is also a copper bearing mineral and it spawns in the lowest levels of the map.  For tin, you are looking for a mineral called cassiterite.  It can spawn anywhere from Y40 up to Y120, but your best bet is still to look for it in a mountainous area because early picks are slow and have low durability so strip and branch mining are not attractive initial options.  It is worth noting that cassiterite has a higher spawn frequency in this pack than it typically does in a default GregTech installation.