Recently started a new game and I want to grab the gems right away... Is this a safe plan ? I'm worried about dragon walls and radiant quests. Like Pinewatch or Dead Crone Rock. Dysfunctional word walls and already dead targets are no fun.

I wouldn't. It's not worth it anyway: I've always found it difficult to obtain gold/silver to craft jewelry for the gems I've found WITHOUT the passive from No Stone Unturned.