ACROSS
 8. <being wrong about> MISAPPREHENDING = MI PERHAPS* ENDING
10. S TEAMS HIP = STEAMSHIP <boat>
11. <likely to get> IN FOR = INFO R
12. <call> DUB = ←BUD←
13. (ADORABLE OLD)* = LABRADOODLE <dog>
16. <flier> AVIATOR A_ VIA TOR
17. <tangle> ENTWINE = TEN* + WINE
19. <heavy> HENCHPERSON HEN + (PERCH)* + SON
21. <I'm frightened> EEK = [-r]EEK
23. ←LAGER← = REGAL <fit for a king>
25. (ELK AT)* + A HOE = LAKE TAHOE <attraction in America>
27. SANDSTONE* <=< STAND ONE'S GROUND <remain firm>

DOWN
 1. AD outside MUSE = AMUSED <was entertaining>
 2. <musical> SPAMALOT = ←TO LA MAPS←
 3. <vault> ARCH = (.l)AR CH(u.)
 4. (TENTH LEAPS)* = THE PLANETS <orchestral suite>
 5. <dye> INDIGO = D inside IN I GO
 6. ←F FIT← = TIFF <argument>
 7. <trouble> AGGRIEVE = "A GREAVE"
 9. B inside PARENTIS* = STEPBAIRN <Iona child>
14. ORDER inside BLAND = BORDERLAND <frontier region>
15. <restaurant> DRIVE-THRU = _D RIVET HR U
16. <saw> APHORISM = MISHAP* outside OR
18. <medicinal preparation> TINCTURE = TIN CURE outside T
20. <compound> HALIDE = HIDE outside AL
22. "NEEDS" = KNEADS <massages>
24. <farm animal> GOAT = G OAT
26. <contact> KISS = K_ + ISS