Complex sentence: To join him, Louisa had to make a forty-day journey across war-ravaged Europe by coach in winter; roving bands of stragglers and highwaymen filled her with "unspeakable terrors" for her son.
Split into simpler sentences: To join him, she made a forty-day journey across war-ravaged Europe by coach in winter. Roving bands of stragglers and highwaymen filled her with "unspeakable terrors" for her son.