If I craft a magical item, what is the check value to overcome Spell Resistance? Let us say the wizard who created a scroll or wand has spell penetration and is an elf. Will this be added on the check?
Although there is no rule written specifically about how to handle spell resistance, to define the save DC of effects created by magic items, the DC is 10 + the level of the spell or effect + the ability modifier of the minimum ability score needed to cast that level of spell.
Based on that we just have to check what is required to overcome spell resistance:
To affect a creature that has spell resistance, a spellcaster must make a caster level check (1d20 + caster level) at least equal to the creature's spell resistance.
Thus, for spell resistance, you could say its the magic item's caster level against the target's Spell Resistance.
But you would only have to roll if the item produces a spell or spell-like ability, as supernatural and extraordinary abilities are not subject to spell resistance.
Only spells and spell-like abilities are subject to spell resistance. Extraordinary and supernatural abilities (including enhancement bonuses on magic weapons) are not. A creature can have some abilities that are subject to spell resistance and some that are not. Even some spells ignore spell resistance;